Are both new as well as existing projects not opening for you in Premiere Elements 10 on Windows 7 (assumed 64 bit)?
Is this a "it worked before but not now" or "it never worked before" matter. If it worked before, how long ago?
Have you looked at the problem with and without the antivirus program disabled?
Do the projects that will not open involve a lot of keyframing of various properties? Does your Windows 7 64 bit computer use a NVIDIA GeForce video card/graphics card?
Please give us that basic information so that we can decide how to proceed.
I have never run into the error message that you are reporting, and I have seen that error message infrequently online. So, right now I am viewing your problem from the generalized point of view of "damaged project".
Answers to the above will help us put your question into perspective.