As of unknown reasons the audio conversion of Virtual CD via iTunes may fail or be incomplete.
Reducing the burn speed in iTunes may solve the problem.
The following tool allows a manual conversion: VC10ACvt.exe
Please copy the file to the Virtual CD program subdirectory System.
After executing VC10ACvt you can choose either a track file (.000) or a conversion information file (.cvi) and then start the conversion.
Unconverted (temprorary) files are stored within the folder for temporary files (see Virtual CD Settings -> Folder).
If possible the complete CD will be converted. Die settings (ouput format, folder for sound files etc.) are taken over from the Virtual CD Settings -> Burn.