custom function error.

[next]

I'm trying to create a custom function to use in my spread sheet, but it return a #NAME error, what am i doing wrong?
[vba]Option Explicit

Function PV_list(WOs As Range) As String
Dim r As Range
Dim list As String
For Each r In WOs
list = list & "^" & r.Value
Next r
PV_list = list
End Function
[/vba]
Here is what it does:
Lets say A1 = a, A2 = b and A3 = c, by typing =PV_list(A1:A3) is should get the following output: a^b^c
This is saved in PERSONAL.xls.

Thanks.