Synchronization lost between sound and picture

When I convert an analog 8 mm video using Windows Movie
Maker 2, and then burn it to VCD format using Ahead Nero
Burning ROM, I lose the synchronization between the
recorded images and the sound. The images run faster
than the sound ... (I record using 25 images/s, format
PAL_B).
I think there is somewhere a mismatch in the assumed
recoprding frequency and the true frequency, but I can't
find where I go wrong.

Thanks for your help in solving this