Couldn’t update QT reference video

I am having trouble exporting a QT Reference Video, after completing my short piece; I encountered this error message below. I have tried a number of tricks but I can export everything else apart from the stereo tracks. I am not sure of the next step, how can I fix this?

An error has occurred:
Assertion failed: compDesc.acomp != NULL
File: fsnapshots/relengsnow5_1 312934509/ppq/MCTop/
ProjeetFi les/../../lledietomposer/Bin/QTcompExport.c, Line:
1599
Create Report Exit To Finder Continue Debugger
