I just notice that in my sample above I used HKLM instead of HKCR.
In the thingy, I used first the "HKCR" key for the associations, but when I notice that the associations doesn't work on other users I changed it to "HKLM\SOFTWARE\Classes\", but as you can see that didn't help either.
But normally "HKCR" key should be the right place for the associations right?
Do you have a virtual maschine or something like that with a fresh Windows 2000 installation?
No, but I could but I could install the VMware
if it even is suitable for tests like this. It will take some time though.
Edit: I tried the thingy in XP and indeed in XP it works, keys gets the rights from the parent keys. I start to think more and more that there is something wrong in my system.