Required software extensions are missing

I don't know why I can't open Logic anymore. I get this message:
Required software extensions are missing
The shared library named "<ILUIEngineLibCarbon><ILUIEngineLibCarbon><URLAccessLib>"could not be found. Please install this library or contact customer support for this product.
I tried to re-install the Logic Express again, but I get the same error message. As for customer support-I can't find any phone no or e-mail.
Anybody help me?
Thanks