exporting quicktime conversion for youtube

I've been uploading HQ video for several years using FCpro5 with no problems. Recently, when I use this same method FC has not included the audio. I have not been able to find the cause or the solution.
Quicktime videos still have sound, but are not compatible for upload, so I have not been able to share videos for several months now.
I use QT conversion, 640x480 VGA, AAC audio 44.100kHz, fast start for internet streaming.
thank you for any help.

thanks steve, I have tried this and used these specs -
Video Settings: H.264, Framerate = Current, Keyframe Every = 29.97
Audio Settings: Format = AAC, Rate = 44.100 Khz,
Frame Controls: On
Resize Filter: Best (Statistical Prediction)
Output Fields: Progressive
Deinterlace: Better (Motion Adaptive)
as a quicktime movie.

I started the task at 10:30 am, and as of 4pm it had not gained any ground (with the completed bar) and still read, 'unknown time' for time remaining.
Is my whole fc package gone haywire ?
I'm missing the ease of fc's quicktime conversion method. any other tips would be greatly helpful.
-daniel.