Create and Error Message Box

[Jamie]

I am working in Word 2002. I have a form with many input fields (291). I
have a
tab order macro in the document to guide through the form. Because of the
tab macro the user cannot tab to a previous field (shift + tab), doing so
tabs them out of the current field and into the next field. I would like to
have an error message come up when the user uses the shift + tab key
combination, stating they can not tab backwards, so the user is left at the
same field they were in when they pressed shift + tab.

Thanks!