When presented with an "Exception Thrown" error message that gives you the option to continue or cancel, you can easily fix it by doing the following:
Go to the File menu and select "Rebuild Database". You should then get the message that all data has been rebuilt, and the error message should not pop-up again.
If you continue to experience the error even after using the "Rebuild Database" option, please go to the Help menu and choose "Send Data Files to Tech Support..." along with a description of what options in MSP are being clicked that cause the error message to appear.