No problem AFnord!
As for my problem - it seems fixed now. The installers seems changed indeed (different MD5SUM) but it must be something else. I had messed up my bi2 folder, and, aparently some of the copy protection is still intact in the EXE, and kicks in if the exe detects that something is wrong.
In case you're wondering, HOW did I mess the game dir: I'm using linux, and had trouble mounting the image file first because of the ogg files having a different case in the cue file. I didn't notice that at first, so I copied everything off the CD image to the game dir, and changed path.txt to point to the current dir. Apparently the game doesn't like that. Or I screwed up something else. Anyways, I figured the problem with the CD-image, and re-installing to a clean state fixed the game ;-) )