Sounds like GB is looking for something that has become damaged.
Was the OS 10.3 installation disk that you used to replace the OS, an original or a Restore disk that you got from some other place?
When you had your crash, what was the problem? Was the HD replaced?
If the answer to that is NO, did you do a Format and Install or an Archive and Install?
What version of GB are you currently trying to launch?
Is there an Instrument Library folder in the /Library/Application Support/GarageBand folder?
What method and medium are you using to try to reinstall GB?


P