And you are exactly right - that truly worked :)
To those with the same problem - the syntax is wrong on the M$ homepage. From C:\inetpub\AdminScripts\, the command which needs to be run, is:
cscript.exe adsutil.vbs set W3SVC/AppPools/Enable32BitAppOnWin64 true
(all in one long line)
Also, you might wanna restart IIS (W3SVC service) after doing this...
File missing...
Also - running Dependency Walker, I found out that gpsvc.dll was missing from the System32 folder. I haven't removed it, and the Win2K8 install isn't even 1 month old. I checked my Vista box, which does have the file. So I copied the from my Vista x86 box (shame on me) - and now even Dependency Walker doesn't complain about missing files...
And guess what - it works! Thanks a lot, BSchwarz, I'm amazed of your skills. I wonder what kind of job (and wage) you have on a daily basis...