tel b is right, if you know the name then you can get a fix for it via that site, however theres nothing much wrong with AVG i dont think so dotn worry there.
Most of these scanners operate differently and wont always show the same results.
Theres a good program called HiJack This. It scans your pc and then you upload the results to a web site where it tells you whats dangerous and whats supposed to be there.
Trojans can be a pain in the rear end to get rid of and in the first instance its better to get the fix first, but in future keep things monitored.
Once you get these sort of things you'll end up spending more time protecting your data than you will actually looking at it lol