Sound won't mux in common(?) formats

[Guy_]

I've demuxed a VCD movie (XVid that went thru TMPGEnc) with TMPGEnc and been resynching the sound to video in Cubase. I saved the finished track and got a huge .wav file (16 bit 48kHz).

I now want to mux it again, but both TMPGEnc ("illegal mpeg audiostream") and M1-Edit ("cannot locate audio packet in input file") refuse
I've tried converting the file to mp3, 224 kbps/44,1 and it still won't work

Actually, I want to burn this movie in VCD format to a DVD-R, so I know I'll need 48 kHz sound in the end. So ideal would be if I could just get the 48 kHz file to mux of course (?).
If necessary I'll convert to 44,1 and let TMPGEnc DVD Author automatically handle the conversion back again to 48 kHz.

But how do I get it to mux in the first place? Is it a format problem, or did Cubase add some stuff to it and do I need to strip a header or something? Windows plays it with no problems, so the sound is in there.

Ideas much appreciated!

[Guy_]

OK, solved it by putting the audio file thru TMPGEnc on itt own, before muxing.