[AccessD] Append Query Problems

I am using A97.  I need to append the records from one table to another
identical in structure.  The query gets about half way done and then stops
with the following error message:  "You tried to assign the Null value to a
variable that isn't a Varient data type."  I am assuming that there is
corruption in one of the records.  How do I go about finding that record?

Tim Thiessen