blasted fansubbers...someone should shoot them for putting h.264 into avi...but that's beside the point
CCCP is pretty much your one-stop shop for video playback (sans the horrific softsub support ala VLC)
Installing it can cause a few problems, but if you go into the start menu folder for CCCP (after it's installed) and go through the 3 configuration things (1 for CCCP, 1 for ffdshow video and 1 for ffdshow audio, disable ffdshow for any codec that you already have) it shouldn't give you a problem.