It seems I have the same problem.
I added an AVI video and trimmed it to about 30 seconds., added text and an MP3 file for background audio. In the PRODUCTION it is fine...when I go to FILE..OUTPUT AS..ad select same settings as above, the resulting MPEG-2 file has no audio (the text is there, though).
Can you help?
Just did another test...outputting to Windows Media format does have audio.
More info...when I output the file to MPG and preview it inside ROxio, I get audio, when I play it in WMP there is no audio.
Also, in case you were wondering...all other MPG files have audio in WMP.