Using Excel 2007 - with compatibilty witn 2003.

Trying to find problems with my VBA code

I have a cell that is set up to accept dates (range named "cdate"). If an
individaul enter 04012009 in that cell, I get an "overfloww" error.

What options do I have to capture this event?

The VBA code breaks at the following line.
If Range("cdate").Value = "" Then