That IIS is reporting HTTP/1.0 at one point and 1.1 at another makes me think that it's possible that two instances of IIS are running in the background. It may even be possible that one of these instances of IIS is 3.0! Then again, I may be horribly off base--but in any case you might try completely uninstalling and reinstalling IIS 4.0.

Good luck. =)