Perhaps I can help here. I had the same problem a few days ago after a crash with Sherlocks, tried everthing, extensions off, even the orginal Sherlock from my OS9 CD refused to start.
I trashed the Sherlock Preferences in the System>Preferences Folder, and everything was normal again. Seems that the Prefs file can get corrupted during a crash with Sherlock. Hope that helps you. Don't forget to set your Sherlock Prefs again afterwards.