Writing Function using vlookup

[perdben]

Hi,

I'm trying to write a simple funtion (my first!).

Function is:

Public Function ytdvol(x1, x2)
    x3 = Application.VLookup(x1, PriceHist, 3, False).Value
    x4 = Application.VLookup(x2, PriceHist, 3, False).Value

ytdvol = x3 + x4
End Function

There is no problem with the vlookup range etc. I get a #VALUE. Any help would be great!

Thanks,
Ben.