Make sure the Name of the text box is not the same as the name of one of the
fields in the form's RecordSource.
If that is not the problem, double-check the name inside the Mid(). It must
be a field name or the name of a control other than itself. You may want to
uncheck the Name AutoCorrect boxes under Tools | Options | General, and then
compact the database to make sure that is not interferring.
If that does not solve the problem, you probably have an issue with
references. More information:
http://members.iinet.net.au/~allenbrowne/ser-38.html
