Sam,
One of the most common reasons for a failure on a common built-in function -
like Left() - is that there is a missing reference.
First of all, open any code module and then click Tools|References. I am
guessing that you do not have a reference set to Microsoft DAO 3.6 Object
Library which is not automatically set as a default for new databases. If
you do not have such a reference set, scroll through the list of references
and click in the checkbox to the left of that reference. If you do already
have a reference set to Microsoft DAO 3.6 Object Library, check your
references for any which may be marked MISSING.
Post back if we need to look into this further!