iCal crashing

The server responded with an error.

The server did not recognize your user name or password for account 'kathie.gallardo@xxxx.xxx.' Make sure you enter them correctly.

Second message:

iCal quit unexpectedly. Click Reopen to open the application again. Click Report to see more detailed information and send a report to Apple. I clicked Report but do not understand what the report says. I sent the report anyway.