Take a look at the divx decoder properties if you have enabled any of the advanced options. If so, turn them off; they may gain you some speed, but also cause a lot of trouble on some systems.
Force the player to rgb (video tab). Use the old rendering method. Try using ffdshow for the video (
http://prdownloads.sourceforge.net/f...7.exe?download) if everything fails.
Divx Player 2a should be able to play AC3 sound with Elecards audio decoder (
http://www.moonlight.co.il/download/OdioDec.zip).