System.NullRefe renceException passing var to web service proxy class

[Ted]

Would someone tell me why I am getting:

"An unhandled exception of type 'System.NullRef erenceException ' occurred in
microsoft.visua lbasic.dll. Additional information: Object variable or With
block variable not set" on this line of code:

lbitemSel = ws.GetImageFile (ListBox1.Selec tedItem.GetType .ToString())

My client code with correct Syntax is:

Dim ws As New GetImageApp.loc alhost.Service1 , dimeAttachment As
Microsoft.Web.S ervices.Dime.Di meAttachment, lbitem As String

lbitemSel = ws.GetImageFile (ListBox1.Selec tedItem.ToStrin g())

When I try it this way I get a syntax error: "Too many arguments to Public
Function ws.GetImageFile ()" when I try it in this way:

Dim lbitemSel As String

lbitemSel = ListBox1.Select edItem.ToString ()

ws.GetImageFile (lbitemSel)

My Web Service object is WS with strLbItemSel declared as a string:

Public Function GetImageFile(By Val lbItemSel As String)

thx,

Ted