Cannot open LilyPond

[Hanno]

Hello,

I just wanted to use LilyPond and I could not open the program. So, I
uninstalled everything (LilyPond.app, org.lilypond.lilypond.savedState,
org.lilypond.lilypond.LSSharedFileList.plist, org.lilypond.lilypond.plist) and
reinstalled it. Same thing. Mac OS X 10.7.3 told me the following: 

08.02.12 18:28:01,667 LilyPond: LilyPond Error
An unexpected error has occurred during execution of the main script

ImportError:
dlopen(/Applications/LilyPond.app/Contents/Resources/lib/
python2.6/lib-dynload/objc/_objc.so,
2): Symbol not found: _objc_sync_notify
  Referenced from:
/Applications/LilyPond.app/Contents/Resources/lib/
python2.6/lib-dynload/objc/_objc.so
  Expected in: /usr/lib/libobjc.A.dylib


I'll send the rest by mail because of the 80 characters here...

Hope, you can help me!
Hanno