The cursor is not on a program line that contains a valid expression. The Instant Watch command expects the cursor to be on an expression whose value you want to see. Choose <OK> on the error message dialog box and reposition the cursor within the expression you want to watch. Tip: In a complex expression, it may be hard to decide where to put the cursor to watch a particular variable or subexpression. You can unambiguously indicate what the Instant Watch command should watch by highlighting it. Just place the cursor on the extreme left or right end of the expression and pressing SHIFT+RIGHT or SHIFT+LEFT.