alpha button macros

Hi,

In my database, I've programmed an alpha macro for a
client directory by last name. And I have a macro
attached that will pull up a message box when no record
is returned for a letter. This macro won't work though,
and when a letter with no data is keyed a blank record
comes up instead. The records are sorted by an
autonumber (primary key) data type. Does this have
something to do with the problem? Is it possible that
the database doesn't recognize that no record exists b/c
of the autonumber? How could I fix it??

Thanks, very much.
Lani