Your reference to the dgsetup.dll file rang a bell as it has previously been discussed http://forum.avast.com/index.php?topic=24612.0 in the forums, so it may be worth a visit to that link. The result of that link was it was likely to be a falsoe positive detection and the latest VPS update no longer detected it as infected.

What version of the VPS do you have ?
Do a manual Update that will also confirm what version you have and update if required.
Or see about avast, the current one is 0645-4 but there is likely to be another one soon.