different avi-types?

Hello! I have rescued a couple of *.avi files from a friend's win-xp system crash ;-|. Most files are the original downstream files from his camera. These files (up to 4GB, but also smaller ones) can not be read by mainactor 3.5 or mainactor 5.0-demo from the suse distributions. Kaffeine shows a black screen but plays the sound - it may be a tribute to my weak system (PII/350). Avi files which were allready treated by Pinacle can be handled by mainactor. My question: Are there different types of avi and/or i need extra libs/ plugins/workarounds ? thx frank