that looks about right...
I think perhaps he might have meant to do this
exc_1_tagFiles = 3
exc_1_tagFile1 = "%SystemDrive%\ATICCC.ins"
exc_1_tagFile2 = "%DPSROOT%\D\V\ATI\attsetup.exe"
exc_1_tagFile3 = "%SystemRoot%\system32\atidemgx.dll"
exc_1_+hwids = 0
exc_1_-hwids = 0
exc_1_+infFiles = 0
exc_1_-infFiles = 0
exc_1_commands = 1
exc_1_command1 = "%DPSROOT%\D\V\ATI\attsetup.exe /s"
You have a copy already??? (confused???)
Um the code posted above would likely fail.
There are no INFs in his 3rd party DriverPack just the exe? (I assume)
Unless he created one named CX_XXXXX.inf and included it in his 3rd party DriverPack folder himself this WILL fail. the +infFiles are probably not needed.
Unless you ONLY want this to install if the target machine has a HWID that can be found in a VALID .inf file found at "%DPSROOT%\D\V\ATI\" and named "CX_XXXXX.inf"
Note "CX_XXXXX.inf" is specific and "CX_?????.inf" is wildcard... 
If I have assumed correctly that this file does not exist then this will ALWAYS fail.
Normaly 3rd party DriverPack are at "%DPSROOT%\D\3\~" but perhaps he did not follow the normal layout. 
notes:
Tag Files;
do you really want it to ONLY install IF the ATI Catalyst Control Center is also installed?
I thought he wanted it to ALWAYS install?
If that is true you must remove the "%SystemDrive%\ATICCC.ins" tag
Obviously the setup.EXE itself must be a tag file .
(We can't very well run an installer that does not exist .)
and system32\atidemgx.dll is a good choice to determine if an ati card is installed 
.
the exc_1_command2 which deletes the installer is probably not needed / redundant.
the finisher will delete all files and folders in "%DPSROOT%\D\*.*
Jeff
PS i am curious how you got a copy of Proximus 3rd party DriverPack already... ???
