Set Field By Name returning Error 102
I have this line:
Set Field By Name [$$CurField ; "0"]
But I am getting the dreaded 102 error message
Data Viewer shows that $$CurField = Books::RetailPrice which is a valid field. Evaluate($$CurField) returns the data in Books::RetailPrice, so I know it is a valid field with valid data at the time of processing. Am I using Set Field By Name wrong?