I can launch the kernel from the command prompt:
○ → /Applications/Mathematica.app/Contents/MacOS/MathKernel
Mathematica 9.0 for Mac OS X x86 (64-bit)
Copyright 1988-2013 Wolfram Research, Inc.
But the application itself will not start in notebook mode. Suggestions? I have re-downloaded the product and checked the md5 checksums to ensure no errors, and reinstalled.