Access 2000 using a from in Access 97

[bill]

cannot convert access 97 database...when i open Access
the access 97 database with Access 2000, all is fine
execpt one simple form...where i search for clients with
their last name. when i type in the first letter of the
last name it pops with the error "The field is too small
to accept the amount of data you attempt to add. try
inserting or pasting less data."

any thoughts why it will not work.

thank you,
bill