"application has unexpectedly quit" error message

[Gerard Tripptree]

Hello all:

I have been having a persistent problem with many OS X applications,
particularly Explorer and Rosetta, quitting  immediately after starting with
the " ... application has unexpectedly quit ... " error message.

The problem exists only when I start-up the ibook from the internal 20GB
hard drive. It does not occur when I start-up from my external 120GB
firewire drive.

I am running OS 10.2.6 on the internal and external drives on a dual usb
iBook with 384MB RAM.

Why does this happen? How can I fix whatever is broken so that this doesn't
happen again?

Thank you.