My file has 2 sheets named "data" & "title"

my "data" sheet has a cell validation that produces a dynamic drop-down list from a name list named "accounting_title" in the "title" sheet.

the validation for the cell in the data sheet is "=OFFSET(ACCOUNTING_TITLE,0,,COUNTA(ACCOUNTING_TITLE))"

It produces the list I need w/o blanks, however the error message does not trigger when i encode an invalid value. Any suggestions on how to remedy this?