Divide by 0 error in ssrs

I have an SSRS Report with a lot of calculations. I have a function with the report that supposed to take care divide by 0 error but I still get the error. The function code is ` Function Divide(Numerator as Double, Denominator as Double) If Denominator = 0 Then Return 0 Else Return Numerator/Denominator End If End Function ` I also have a expression that is `=Code.Divide(ReportItems!Textbox41.Value, Fields!mnypotientalRentTotal.Value)' I have no idea how to fix the divide by 0 error any ideas would be great.