Actually I came across several occurrences where there was some minor error with the AVI that CCE could encode easily, and TMPG stop recognizing beyond the corrupted frame, or it could be VBR sound that is braking the situation, use virtualdub or mod, and when you open the file click ok in virtualdub or yes in mod, then select direct stream both for video and audio and save the file as an AVI, when you play the file it would be out of sync, but on encoding it using TMPG it would be ok.