Premiere Elements 11 on Windows 8 (assumed 64 bit).
What are the properties of the source media involved -
Interlaced or Progressive
Pixel Aspect Ratio
Sometimes posting the brand/model/settings of the camera that recorded the video will give us enough media troubleshooting information rather than downloading video and audio properties readout programs. Let us see.
Some typical drill questions
1. Does the problem exist with or without the antivirus and firewalls disabled?
2. Do you have the latest version of QuickTime installed on your computer with Premiere Elements 11?
3. Are you running the programs as administrator?
4. Is this a "it worked before but now" or "it never worked before" issue?
5. Is your video card/graphics card driver version up to date according to the web site of the manufacturer of the card or the manufacturer of the computer?
6. What is a description of your computer resources? Is your program installed to the default Local Disk C location?
Let us start here and then decide what next.
Any questions or need clarification on any of the above, please do not hesitate to ask.