Scripts - Expression Evaluator Error

The program has detected a syntax error in your expression in the 'Process file when expression is non-zero' field in the Scripts-Advanced tab. See Expression Evaluator for more information.

In most cases this is caused by problems with the ( ) characters. If you are having trouble dismissing closing the Advanced tab because the error message reappears, make a very simple entry such as
E1

This will surely be OK and permit you to close the dialog so you can return to your work later.