Class Factory Error

Class factory cannot supply requested class.
I tried to play some videos (two Avi’s) but this
message stopped me. I don’t understand it. Some avis play but these two don’t. I read somewhere
that it has to do something with outlook but I dont use this programe. What should I do??

Class factory errors can mean a lot of different things, from missing codec to incomplete avi’s. Your best bet would be to feed the file into a diagnostic utility like the ones on this page to find out.
http://www.moviecodec.com/questions/neededcodec.html