AV loss-of -sync when joined AVIs

[JimmyBarnes]

Hi

Have a movie in 3 parts (XviD AVIs) with AC3 audio. When played individually, each part has AV in sync. If I join the parts in order to give a single AVI, the AV is well out-of-sync, from the very beginning. I have joined AVIs like this before and not had this problem. :confused:

What is wrong and how to fix?

thanks

JB