On what computer operating system is your Premiere Elements 10 running?
I do not think it is involved here, but I will ask away...what video card/graphics card does your computer use....NVIDIA GeForce or other?
Please determine if your video was recorded with a variable rather than constant frame rate. If variable, then take your video through
HandBrake to obtain as your source file a H.264.mp4 file set with a constant rather than variable frame rate.
Premiere Elements has problems with variable frame rate. The symptoms can range from audio out of sync to not being able to import
the video at all.
Please review and consider and then we can decide what next.
Add On...Also do not overlook the project preset matching the properties of the source media part of the troubleshooting equation....and
viewing and listening to a Timeline content which has been Timeline rendered.