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-Information FAQ http://forums.adobe.com/message/4200840
Addressing your Premiere Elements 9 question directly.
What computer operating system is your Premiere Elements 9 running on and are you running Premiere Elements 9 as the 9.0.1 Update?
Is this problem "it worked before but not now" or "it never worked before"?
Have you checked out the Playback Settings via right clicking the Edit Mode Monitor and selecting Playback Settings? If so, did the look like this:
Are you working with the rendered or unrendered Timeline when you run into your issue?
Depending on your answers to the above, questions like the following would need answers:
a. What are the properties of your source media (video and audio) on that Timeline?
b. What are you setting as the project preset?
c. Is your computer optimized and are your video and audio card drivers up to date?
We will be watching for your follow up.