[MacDV] Sound problems

[merelyn davi]

I have been having trouble with sound being distorted when it is  
exported to iDVD.

Before I exported the movie there were no problems with sound in iMovie.

I did a preview in iDVD and the sound was very distorted and in parts  
there was a terrible noise almost a grinding sound.

I closed off iDVD went back into iMovie and deleted some added  
sounds. and 2 music tracks.

The movie is just short of 1 hour.

I then went back into iDVD and previewed it and all was well.

I went back into iMovie, left out the sounds and put 2 new audio  
tracks into the movie. and when I went back into iDVD I had the same  
problem.

Has anyone had the same problem?

I haven't had the problem before I upgraded and am wondering if this  
is something that is wrong with iDVD5.0.1

Are there any suggestions anyone can give me please, as I really  
would like to use the added audio.

Thanks

Merelyn