I'm not using the DriverPack and have my own Driver Base that I use but I am having the same proble you guys seem to be experiencing.  Has anyone found a resolution to this issue.  I can get the Dell Lattitude D620/D630 Sigmatel Driver (DriverVer=02/19/2007,5.10.0.5401) to work?  I have managed to get it to install correctly during setup when other Sigmatel Drivers aren't present, but when other Sigmatel Drivers are present in different folders the "Sigmatel High Definition Audio Codec" fails to install correctly.

In my scenario:Dell D630 systems have Sigmatel HD Audio (Ven 8384 Dev 76A0) and I am using the following Sigmatel Driver: DriverVer=02/19/2007,5.10.0.5401
This driver is in the C:\Drv\31 Directory.

Gateway E-6610 systems that have Sigmatel HD Audio (Ven 8384 Dev 7680) and I am using the following Sigmatel Driver: DriverVer=09/07/2006,5.10.5208.0
This driver is in the C:\Drv\32 Directory.

The E-6610 's Sigmatel Audio installs and works perfectly only after removing all references to the 7680 device id from the D620 Driver INF and INI files.

If the C:\Drv\32 directory or the path to the 32 directory in the registry is removed before setup runs, the D630 driver installs and works perfectly.  With the 31 directory present, the Audio CODEC shows up with the yellow nasty, and reports that it is configured incorrectly and has no files listed in the Driver Files Details Box.

All references to the 76A0 device id was removed from the E-6610 driver INF and INI files.
All references to the 7680 device id from the D620 Driver INF and INI files.

Both drivers install and work perfectly on thier respective systems when installed manually provided setup did not try to install them.  If setup attempted to install them, then updating the Audio CODEC does not resolve the issue.

Here are the appropriate sections from the setupapi.log:

[2007/11/30 16:22:24 484.1581 Driver Install]
#-019 Searching for hardware ID(s): hdaudio\func_01&ven_8384&dev_76a0&subsys_102801f9&rev_1002,hdaudio\func_01&ven_8384&dev_76a0&subsys_102801f9
#-018 Searching for compatible ID(s): hdaudio\func_01&ven_8384&dev_76a0&rev_1002,hdaudio\func_01&ven_8384&dev_76a0,hdaudio\func_01&ven_8384,hdaudio\func_01
#-198 Command line processed: C:\WINDOWS\system32\services.exe -setup
#I022 Found "HDAUDIO\FUNC_01&VEN_8384&DEV_76A0" in C:\Drv\31\sthda.inf; Device: "SigmaTel High Definition Audio CODEC"; Driver: "SigmaTel High Definition Audio CODEC"; Provider: "SigmaTel"; Mfg: "SigmaTel"; Section name: "STHDA".
#I087 Driver node not trusted, rank changed from 0x00002001 to 0x0000a001.
#I023 Actual install section: [STHDA.NT]. Rank: 0x0000a001. Effective driver date: 02/19/2007.
#-166 Device install function: DIF_SELECTBESTCOMPATDRV.
#I063 Selected driver installs from section [STHDA] in "c:\drv\31\sthda.inf".
#I320 Class GUID of device remains: {4D36E96C-E325-11CE-BFC1-08002BE10318}.
#I060 Set selected driver.
#I058 Selected best compatible driver.
#-166 Device install function: DIF_INSTALLDEVICEFILES.
#I124 Doing copy-only install of "HDAUDIO\FUNC_01&VEN_8384&DEV_76A0&SUBSYS_102801F9&REV_1002\4&8F2C18F&0&0001".
#-011 Installing section [STHDA.NT] from "c:\drv\31\sthda.inf".
#E358 An unsigned or incorrectly signed file "c:\drv\31\sthda.inf" for driver "SigmaTel High Definition Audio CODEC" blocked (server install). Error 0x800b0100: No signature was present in the subject.
#E122 Device install failed. Error 0x800b0100: No signature was present in the subject.
#E157 Default installer failed. Error 0x800b0100: No signature was present in the subject.

[2007/11/30 16:23:00 580.170 Driver Install]
#-019 Searching for hardware ID(s): hdaudio\func_01&ven_8384&dev_76a0&subsys_102801f9&rev_1002,hdaudio\func_01&ven_8384&dev_76a0&subsys_102801f9
#-018 Searching for compatible ID(s): hdaudio\func_01&ven_8384&dev_76a0&rev_1002,hdaudio\func_01&ven_8384&dev_76a0,hdaudio\func_01&ven_8384,hdaudio\func_01
#-199 Executing "C:\WINDOWS\system32\setup.exe" with command line: setup.exe -newsetup -mini
#I022 Found "HDAUDIO\FUNC_01&VEN_8384&DEV_76A0" in C:\Drv\31\sthda.inf; Device: "SigmaTel High Definition Audio CODEC"; Driver: "SigmaTel High Definition Audio CODEC"; Provider: "SigmaTel"; Mfg: "SigmaTel"; Section name: "STHDA".
#I087 Driver node not trusted, rank changed from 0x00002001 to 0x0000a001.
#I023 Actual install section: [STHDA.NT]. Rank: 0x0000a001. Effective driver date: 02/19/2007.
#-166 Device install function: DIF_SELECTBESTCOMPATDRV.
#I063 Selected driver installs from section [STHDA] in "c:\drv\31\sthda.inf".
#I320 Class GUID of device remains: {4D36E96C-E325-11CE-BFC1-08002BE10318}.
#I060 Set selected driver.
#I058 Selected best compatible driver.

[2007/11/30 16:23:01 580.305]
#-199 Executing "C:\WINDOWS\system32\setup.exe" with command line: setup.exe -newsetup -mini
#I060 Set selected driver.
#-019 Searching for hardware ID(s): hdaudio\func_01&ven_8384&dev_76a0&subsys_102801f9&rev_1002,hdaudio\func_01&ven_8384&dev_76a0&subsys_102801f9
#-018 Searching for compatible ID(s): hdaudio\func_01&ven_8384&dev_76a0&rev_1002,hdaudio\func_01&ven_8384&dev_76a0,hdaudio\func_01&ven_8384,hdaudio\func_01
#I022 Found "HDAUDIO\FUNC_01&VEN_8384&DEV_76A0" in c:\drv\31\sthda.inf; Device: "SigmaTel High Definition Audio CODEC"; Driver: "SigmaTel High Definition Audio CODEC"; Provider: "SigmaTel"; Mfg: "SigmaTel"; Section name: "STHDA".
#I087 Driver node not trusted, rank changed from 0x00002001 to 0x0000a001.
#I023 Actual install section: [STHDA.NT]. Rank: 0x0000a001. Effective driver date: 02/19/2007.
#-019 Searching for hardware ID(s): hdaudio\func_01&ven_8384&dev_76a0&subsys_102801f9&rev_1002,hdaudio\func_01&ven_8384&dev_76a0&subsys_102801f9
#-018 Searching for compatible ID(s): hdaudio\func_01&ven_8384&dev_76a0&rev_1002,hdaudio\func_01&ven_8384&dev_76a0,hdaudio\func_01&ven_8384,hdaudio\func_01
#-166 Device install function: DIF_SELECTBESTCOMPATDRV.
#I063 Selected driver installs from section [STHDA] in "c:\drv\31\sthda.inf".
#I320 Class GUID of device remains: {4D36E96C-E325-11CE-BFC1-08002BE10318}.
#I060 Set selected driver.
#I058 Selected best compatible driver.
#-124 Doing copy-only install of "HDAUDIO\FUNC_01&VEN_8384&DEV_76A0&SUBSYS_102801F9&REV_1002\4&8F2C18F&0&0001".
#E360 An unsigned or incorrectly signed file "c:\drv\31\sthda.inf" for driver "SigmaTel High Definition Audio CODEC" will be installed (Policy=Ignore). Error 0x800b0100: No signature was present in the subject.
#-336 Copying file "C:\WINDOWS\Driver Cache\i386\portcls.sys" to "C:\WINDOWS\system32\drivers\portcls.sys" via temporary file "C:\WINDOWS\system32\drivers\SET107.tmp".
#E249 Failed to apply security to file "C:\WINDOWS\system32\drivers\portcls.sys". Error 1307: This security ID may not be assigned as the owner of this object.
#-336 Copying file "c:\drv\31\sthda.sys" to "C:\WINDOWS\system32\drivers\sthda.sys" via temporary file "C:\WINDOWS\system32\drivers\SET114.tmp".
#E360 An unsigned or incorrectly signed file "c:\drv\31\sthda.sys" for driver "SigmaTel High Definition Audio CODEC" will be installed (Policy=Ignore). Error 0x800b0100: No signature was present in the subject.
#-336 Copying file "c:\drv\31\stacapi.dll" to "C:\WINDOWS\system32\stacapi.dll" via temporary file "C:\WINDOWS\system32\SET115.tmp".
#E360 An unsigned or incorrectly signed file "c:\drv\31\stacapi.dll" for driver "SigmaTel High Definition Audio CODEC" will be installed (Policy=Ignore). Error 0x800b0100: No signature was present in the subject.
#-336 Copying file "c:\drv\31\staco.dll" to "C:\WINDOWS\system32\staco.dll" via temporary file "C:\WINDOWS\system32\SET116.tmp".
#E360 An unsigned or incorrectly signed file "c:\drv\31\staco.dll" for driver "SigmaTel High Definition Audio CODEC" will be installed (Policy=Ignore). Error 0x800b0100: No signature was present in the subject.
#-166 Device install function: DIF_REGISTER_COINSTALLERS.
#I056 Coinstallers registered.
#-148 Loading coinstaller modules for "SigmaTel High Definition Audio CODEC".
#E360 An unsigned or incorrectly signed file "C:\WINDOWS\system32\staco.dll" for driver "SigmaTel High Definition Audio CODEC" will be installed (Policy=Ignore). Error 0x800b0100: No signature was present in the subject.
#-166 Device install function: DIF_INSTALLINTERFACES.
#-011 Installing section [STHDA.NT.Interfaces] from "c:\drv\31\sthda.inf".
#I054 Interfaces installed.
#-166 Device install function: DIF_INSTALLDEVICE.
#E151 Coinstaller 1 of 1 failed. Error 31: A device attached to the system is not functioning.

[2007/11/30 16:28:27 960.3 Driver Install]
#-019 Searching for hardware ID(s): hdaudio\func_01&ven_8384&dev_76a0&subsys_102801f9&rev_1002,hdaudio\func_01&ven_8384&dev_76a0&subsys_102801f9
#-018 Searching for compatible ID(s): hdaudio\func_01&ven_8384&dev_76a0&rev_1002,hdaudio\func_01&ven_8384&dev_76a0,hdaudio\func_01&ven_8384,hdaudio\func_01
#-198 Command line processed: C:\WINDOWS\system32\services.exe
#I022 Found "HDAUDIO\FUNC_01&VEN_8384&DEV_76A0" in C:\Drv\31\sthda.inf; Device: "SigmaTel High Definition Audio CODEC"; Driver: "SigmaTel High Definition Audio CODEC"; Provider: "SigmaTel"; Mfg: "SigmaTel"; Section name: "STHDA".
#I087 Driver node not trusted, rank changed from 0x00002001 to 0x0000a001.
#I023 Actual install section: [STHDA.NT]. Rank: 0x0000a001. Effective driver date: 02/19/2007.
#-148 Loading coinstaller modules for "Audio Device on High Definition Audio Bus".
#E358 An unsigned or incorrectly signed file "C:\WINDOWS\system32\staco.dll" for driver "Audio Device on High Definition Audio Bus" blocked (server install). Error 0x800b0100: No signature was present in the subject.
#E161 Processing of call to class installer failed. Error 0x800b0100: No signature was present in the subject.

I hope this helps.  I would really like to find a resolution to this issue and will help where I can.

Thanks!