This is odd. Do you happen to know who currently holds the rights to these AD&D games?
Here, I made some scans:
I've tested it on Vista 32bit and 7 32 & 64 bit. The game runs great. However, other than this, absolutely nothing noticeable is changed. All of the contents of the DVD are the same down to the readme, the license agreement during install, and it even shows the Icewind Dale trailer at the end and asks if you want to register with Black Isle. The only thing on the box that's changed is a DVD-Rom logo and the system requirements.
There's zero mention of who released this version. It still gives complete credit to gamesas and Black Isle.This doesn't seem to be the only game being released like this. A search for "gamesas" in UK amazon shows more DVD version results:
http://www.amazon.co.uk/s?ie=UTF8&search-type=ss&index=video-games-uk&field-keywords=gamesas
There's also been rumors around the internet that you guys were the ones doing the re-release but that's not possible:
http://www.rockpapershotgun.com/2009/10/27/planescape-torment-re-release/