Hello. I have downloaded a couple of clips of avi ...

Hello. I have downloaded a couple of clips of avi files that were encoded using xvid codec. And everytime I click on the file to open it and watch it, Windows alerts me that there has been a problem with windows and that it must close immediately.
I can play the files with no problem but Windows closes and it is annoying. I have Windows XP and have reinstalled xvid codec. What is the problem? Thanks.