Firstly, thanks for your great project! It is very useful.
I have experienced this issue in the last months. The diagnostics I performed showed the HTTP server slamming the connection shut part the way through the download, and it is consistent.
It does seem like a resource exhaustion (ie server overloaded) issue though.
Heimi/Wim - it's worthwhile passing this information on (at least the server closing the connection early), and I imagine that it'll end up costing more bandwidth, due to the re-downloading. It's a pity they didn't resolve it before.
Many thanks, Daniel