Check to see if a method in the control or form is calling a procedure or function that is located in an external procedure (*.prg) file. 'THISFORM' or 'THIS' doesn't work in external procedures or functions, even when they are called by object methods.

If this is the case, but you still need to manipulate the form in the procedure or function, try passing an object reference of the form to the external function or procedure instead. My guess is the reason why you didn't have an error on the first or second try is that either the event or conditions that result in the external function or procedure call did not occur (or maybe the third time was the charm...).

Hopefully this helps,

Thomas Allan