bump - I don't think this thread is dead, since jdb264c's problem wasn't resolved.
I have had this problem with every computer I've had since the gray checkbox first appeared in AVS.
It doesn't say (experimental) anymore, but it still doesn't do anything.
I set cfg_trans=1 in the [AVS] section of winamp.ini, but all that did was add a gray checkmark to the gray checkbox, and it still doesn't do anything. I can't think of anything else to try.
I have had this problem with:
Windows XP Home SP2
Windows XP Pro SP2,SP3
Windows XP MCE SP2