iCal error saving calendar data

When I try to do anythig with iCal i get the following error:

"There was an error saving calendar data. Calendar encountered a critical error while saving to the database, and recent chagnes may be lost. More invormation maybe available in teh console."

The Console readout says:

4/28/13 2:59:02.105 PM iCalExternalSync[11881]: CoreData: error: (11) Fatal error. The database at /Users/navytennis/Library/Calendars/Calendar Cache is corrupted. SQLite error code:11, 'database disk image is malformed'

Appreciate any tips to move forward. thanks, jwc