Overflow paa en double i funktionskald

Hejsa

I nedenstaaende funktion faar jeg overflow som om funtionen er defineret som en integer, hvilket den jo ikke er! Hvad gaar der galt?

Public Function AreaCalc(Sampler As String, PCount As Long) As Double
Dim Diameter As Double
Dim Efficiency As Double

Diameter = DLookup("[Diameter]", "TblSamplers", "[Sampler] = '" & Sampler & "'")
Efficiency = DLookup("[efficiency]", "TblSamplers", "[Sampler] = '" & Sampler & "'")


AreaCalc = PCount / ((3.1415926535 * (Diameter / 2) ^ 2) * Efficiency)

End Function