These questions below may be for a different product... but the information you need to supply is the same, for the products you use
More information needed for someone to help... please click these links and provide the requested information
-Information FAQ http://forums.adobe.com/message/4200840
-Effective questions http://forums.adobe.com/thread/416679
-How to get help quickly http://forums.adobe.com/thread/419406
What operating system are you using? The 64 or 32 bit version? Have you ensured you have even the updates that don't install automatically?
Do you have the latest version of Quicktime?
How fast is your processor, how much RAM do you have and how much clean, free, freshly defragmented space is on your C drive?
What other Adobe software do you have?
What antivirus program are you using?
Welcome to the forum.
Along with the answers to the questions above, also see this article: http://forums.adobe.com/message/4943624#4943624
One of the most common causes for PrE not Opening properly, is an obsolete video driver.