It's probably some kind of a codec issue, but rather try and sort out what codec it is that's being problematic, just download VLC Player instead. It should be able to play almost anything you throw at it, and you don't have the potential malware infestation threat like you do with Windows Media Player.
Recently I started getting an error when I play AVI's. I have uninstalled and reinstalled wmp 10 that didn't work, I installed wmp 11 that didn't work, i also did a roll back to when the error wasn't happening that didn't work any ideas? This is what the error log I am getting looks like. I am running Windows XP Home SP 2 2.4ghz processor 768mgs RAM. Thanks for any help possible
<?xml version="1.0" encoding="UTF-16"?>
<DATABASE>
<EXE NAME="wmplayer.exe" FILTER="GRABMI_FILTER_PRIVACY">
<MATCHING_FILE NAME="custsat.dll" SIZE="28672" CHECKSUM="0xA3A3A810" BIN_FILE_VERSION="1.0.18.1900" BIN_PRODUCT_VERSION="1.0.18.1900" PRODUCT_VERSION="1.00.0018.1900" FILE_DESCRIPTION="custsat" COMPANY_NAME="Microsoft Corporation" PRODUCT_NAME="Microsoft(R) CustSat DLL" FILE_VERSION="1.00.0018.1900 (xpsp.040420-1835)" ORIGINAL_FILENAME="custsat.dll" INTERNAL_NAME="custsat" LEGAL_COPYRIGHT="

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic