How to suppress a running total field

I need to suppress a running field total from showing if a datafield is empty

The datafield is {ControlHeadA.package}
and the runningtotal filed is #Qvalue and located in the report footer

I have tried this formula

if {ControlHeadA.package} > "" then
formula = True 'suppress the value
Else
formula = False 'do not suppress the value
End If

but get error message a number , currency..... is expected here

Can somebody please help