OK, here's the deal. I recently upgraded my Mac Pro from Leopard to Snow Leopard (mainly to get ready for Lion, I've been running SL on my MacBook Pro for ages). I never had any problems with Logic 8 (or Final Cut Studio 5.1 for that matter) on my MBP running SL. But after upgrading my Mac Pro, I would get nothing but crashes any time I tried to bring up an Open or Save dialog box in any of Apple's pro apps. The crash log would always show something like this:
Thread 0 Crashed: Dispatch queue: com.apple.main-thread
0 libobjc.A.dylib 0x91795917 objc_msgSend + 23
1 com.apple.AppKit 0x95e11649 -[NSView _recursiveBreakKeyViewLoop] + 219
2 com.apple.AppKit 0x95e10a2b -[NSWindow dealloc] + 641
3 com.apple.AppKit 0x961ab298 -[NSSavePanel _bonafiedDealloc] + 75
4 com.apple.CoreFoundation 0x931779d8 CFRelease + 152
5 com.apple.CoreFoundation 0x931a45bd _CFAutoreleasePoolPop + 253
6 com.apple.Foundation 0x95942f9f NSPopAutoreleasePool + 393
7 com.apple.Foundation 0x95942d8a -[NSAutoreleasePool drain] + 130
8 com.apple.AppKit 0x95c66539 -[NSApplication run] + 627
9 com.apple.prokit 0x009bb3f6 NSProApplicationMain + 326
10 com.apple.WaveBurner 0x000027fa 0x1000 + 6138
11 com.apple.WaveBurner 0x00002721 0x1000 + 5921
After pulling my hair out for hours, I finally solved the problem. I discovered that there was a /System/Library/PrivateFrameworks/ProKit.framework as well as a /S/L/PF/ProKit(SnowLeopard).framework folder on my Mac Pro. However, on my MBP, there was only the expected ProKit.framework folder.
So, (via the Terminal, sudo mv, etc.) I renamed ProKit.framework to ProKitFOO.framework and renamed ProKit(SnowLeopard).framework to ProKit.framework. Boom! Everything started working fine.
I Googled for a fix like this for hours earlier, so here's hoping that this might end up helping someone else out there, perhaps thinking of upgrading to SL to make way for Lion. Don't ask me why this ProKit installation was goofy, but at least now there may be a workaround.