Begin by installing the 5.5.2 update, and then answer all of the questions in the first post that John linked to.
You can install Premiere Pro updates by opening Bridge or any other CS5.5 application and choosing Help > Updates.
Did you find any solution?
I´ve been working on a project two last days, the project have been freezed sometimes, but always been starting again after next startup. But now, it wont. I have updated to 5.5.2, but no change. I open the project, the timeline loads up, but then it shuts down.
Premiere works with another project, but this project dont. Is it the project file? How can i save my timeline?
Showing this error:
Process: Adobe Premiere Pro CS5.5 
Path: /Applications/Adobe Premiere Pro CS5.5/Adobe Premiere Pro CS5.5.app/Contents/MacOS/Adobe Premiere Pro CS5.5
Version: 5.5.2 (5.5.2)
Code Type: X86-64 (Native)
Parent Process: launchd 
Date/Time: 2012-12-11 10:41:17.230 +0100
OS Version: Mac OS X 10.7.5 (11G63)
Report Version: 9
Interval Since Last Report: 377926 sec
Crashes Since Last Report: 11
Per-App Interval Since Last Report: 34 sec
Per-App Crashes Since Last Report: 1
Anonymous UUID: F669E2C6-CA16-446E-8F89-B358489735AC
Crashed Thread: 0 Dispatch queue: com.apple.main-thread
Exception Type: EXC_CRASH (SIGSEGV)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Application Specific Information:
objc: garbage collection is OFF
The first thing to check is what is different about the project that works and the one that doesn't? Is the source footage a different format or codec? Do you have different, or more or less effects applied?
What was the last thing you did in the bad project before you saved it?
Please answer as many questions from the following link as you can. You've already answered the first 3: