InfoPath Dev

I have several rules which lookup account names from Access tables. I need to pop a message on a "Not Found" when the user enters wrong info into a text box. What is the best way to do this...and how do you do it?

Thanks so much for all the help.

Do you use a query or lookup button?

Typically I would use a rule on the button after the query, where query field account name in not blank and data field account name is(nothing found).

Then the action would be your message or an expression box

concat("What were you thinking entering ", ActName, "? That does not work!")

If you create your form from a data source then if you enter wrong data into the query field, and then query the information, this error message will show:  The specified query did not return any data.  You can revise the query, or you can click New record to enter a new record.  Then once you close that error the data fields that should have been returned will disappear from the form until you run the query again with correct data.  This will not make all fields disappear, only the ones that are from the data source.

 I do not know if it is different if you don't create the form from the datasource.