What is the origin of the MP4 that you're using as your source video? Is it from a camcorder?
Some MP4s -- such as those created by programs like SnapIt and FRAPS -- use a variable frame rate as part of their compression, and that can be problematic.
The mp4 is an old film I put together in windows movie maker that I wanted to fix up in elements.
Ive since changed the audio source in the elements 15 trial that I downloaded, there was a message next to one of the sources saying (not working).
I clicked around a little bit and it dissapeared and now it works.
I hope it will work when the trial is finished and I go back to the old version?
Will i need elements 15 to work on my old films?
I can't vouch for how non-camcorder video will behave in Premiere Elements.