Erroneous Division by Zero Error?

Can someone explain why I am receiving this error...

'The Value expression for the textbox 'textbox2' contains an error: Attempted to divide by zero.'

on this expression...

=IIF(First(Fields!V2.Value, "MyDataSet") <> 0, Last(Fields!V2.Value, "MyDataSet")/First(Fields!V2.Value, "MyDataSet"), 0)

In this case, both values are equal to 0 but  the check should avoid the actual division when the divisor is 0, should it not?

Thanks in advance for your assistance.

Anthony Sullivan