Runtime Error 800a100c!!!!!!!!

[tashy]

Can anyone help in figuring out what is wrong with the script below:

For I = 0 To UBound(arrArray )
If Val(arrArray(I) ) = Val(varValue) Then
Array_Exists = True
Exit Function
End If
Next
Array_Exists = False
End Function

The accompanying error is

Microsoft VBScript runtime error '800a001c'

Out of stack space: 'Val'

Any info will be really appreciated.
Thanks.