[VB.Net] How to Read Text from a TextBox

[qiangqiang101]

I have a module

 

Option Strict Off 
Option Explicit On 
Module TXTread 

   Public Function ReadTXTValue(ByRef KEY As String, ByRef Variable As String) As String 
       Dim NF As Short 
       Dim Temp As String 
       Dim LcaseTemp As String 
       Dim ReadyToRead As Boolean 

AssignVariables: 
       NF = FreeFile() 
       ReadTXTValue = "" 
       KEY = "[" & LCase(KEY) & "]" 
       Variable = LCase(Variable) 

EnsureFileExists: 
       FileOpen(NF, frmStart.txtMessage2.Text, OpenMode.Binary) 
       FileClose(NF) 
       SetAttr(frmStart.txtMessage2.Text, FileAttribute.Archive) 

LoadFile: 
       FileOpen(NF, frmStart.txtMessage2.Text, OpenMode.Input) 
       While Not EOF(NF) 
           Temp = LineInput(NF) 
           LcaseTemp = LCase(Temp) 
           If InStr(LcaseTemp, "[") <> 0 Then ReadyToRead = False 
           If LcaseTemp = KEY Then ReadyToRead = True 
           If InStr(LcaseTemp, "[") = 0 And ReadyToRead = True Then 
               If InStr(LcaseTemp, Variable & "=") = 1 Then 
                   ReadTXTValue = Mid(Temp, 1 + Len(Variable & "=")) 
                   FileClose(NF) : Exit Function 
               End If 
           End If 
       End While 
       FileClose(NF) 
   End Function 
End Module  

 

And I put this on my form1

Me.txtCheck4Update.Text = ReadTXTValue("SERVER SET", "HttpAddressFile")

 

And My Setting in the txtMessage2.text is

[sERVER SET]

HttpAddressFile=http://www.something.com/server.txt

 

But when I debug my Application

A Warning Shows up

"ArgumentException was unhandled"

[mandelbrot]

Which line does this happen on?