Hurrah, the first ULead question for ages! I finally feel useful again!
You don't mention if the sound problem occurs before or after the you render the movie. But there are a couple of possibilities
1. Check that your directx audio drivers are at the latest level.
2. Make sure that you are using the correct project settings. I prefer to capture and edit in lossless AVI. From the FIle menu select Project Properties.
3. Set the Edit File format: to Microsoft AVI files and click the Edit button
4. Click the AVI tab and set the Audio format to PCM.
5. Click OK twice, render your movie and enjoy.
Let us know how you get on.
COMPAQ something or other with 500Gb Boot Disk, 1Tb external Firewire Disk, 4Gb Memory and a super duper sound card, 19" TFT Monitor etc etc etc
Sony TRV33e : Sony TRV310e : Canon XM2
Sony Vegas Studio editions to v11
Remember, there is always more to learn than there is to teach.