Not under validation.
You have two options:
Both would use this basic expression: If ( balanceDue = 0 ; "Paid" ; "" )
1) define a field of type calculation and enter the above expression, selecting "text" as the calculation field's return type.
2) Define a field of type text and use the above expression as an auto-enter expression. Make sure to also clear the "Do not replace existing value..." option.
Note option 2 will fail to update automatically if its calculation refers to a field in another record.
If this is a calculation field (as I would expect it to be) there is something funny going on, as FM is expecting a Boolean result. Are you defining the field PaidStatus as a calculation field?
"Your DA Man" Phil...thanks.
Sometimes even the simplest things esccape
Sorbsbuster>I defined it as a text with validation...and as you mentioned it should of been a calculation
Changed to Calculation and it worked.