Try to get the Dynamic... properties values after the error messages.
You also can try to put another grid on the form with the same RecordSource (but without GridHighlighter) and put the Dynamic... expressions from the first grid in the new one manually. You will need to use some other property (instead of "this.parent.GridHighlighter1.nRecno")to store nRecno (current record number) though. Then try to test and see if it gives the same error.

Since the above might be difficult to do, could you also send me your form and all related files so I could try to reproduce the error?

>I have tried, to do this, but I cannot get access to the VFP Debugger when the Message appears, and the only options on the dialog are OK and CANCEL, but clicking on either button does the same thing.
>
>The Actual Error is:
>Expression is Invalid. Use a Valid Expression for DYNAMICFORECOLOR
>property.
>
>OK CANCEL
>
>click either button and you get the same message, but for the DYNAMICBACKCOLOR, then the DYNAMICFONTBOLD properties.
>
>This does not happen all the time, I can run the form and everything works fine, then the next time, this happens. Run it again the next 2 or more times and it works, the problem is an intermittent one.
>
>Any other ideas ?
>
>Thanks
>Simon.