I did take all the tracks into Audacity, and export them out, but not 100 % as I couldn't face doing it to my voice as I had chopped it up into lots of bits. I then redid the soundtrack with some MP3 and my voice wavs, retried same problem, but blame my tardiness for that!. So I thought I would try a mix down in Wav format from Cool Edit and although a large file seemed to work OK. So I then tried taking the Cool Edit Wav into Audacity and exporting as MP3 replaced the track on the timeline and created one more time. Watched it with trepidation but success, Alleluia! I wasn't doing things differently to how I have in the past, but did buy a sound effect which may have caused the problem. But thanks to you all for your help in pointing me in the right direction. Melanie