LOL, well you we're helping me in the first place
Besides, yeah I am gettin kinda comfortable, whenever help is needed there is always someone around to help, you don't find that very often anymore. So to express my gratitude I've cleaned it up, still the Dialog is a simple one

Code:

Break On

$System = CreateObject("Kixforms.System")
If Not $System
$nul= MessageBox("KiXforms.Net Not Initiated. This Script Will Now Close.","Error",16)
Quit()
EndIf
$nul = $System.Application.EnableVisualStyles

GLOBAL $oAutoIT, $sMessengerTitle, $iControlMessage, $log
$sMessengerTitle="Messenger-service"
$iControlMessage=65535

$oAutoIT=CreateObject("AutoItX3.Control")
If @ERROR OR VarType($oAutoIT)<>9
? "Cannot create AutoIT object - no registered perhaps?" + @CRLF
Exit @ERROR
EndIf

; Set some useful options.
$=$oAutoIT.Opt("MouseCoordMode",0)
$=$oAutoIT.Opt("WinTitleMatchMode",4)

; Timer to catch messages
$Timer = $System.Timer
$Timer.Interval = 1000 ;1000ms = 1s
$Timer.Tick = "CatchMSG()" ;the event that fires every second
$Timer.Start

$Form1 = $System.Form()
$Form1.Left = 368
$Form1.StartPosition = 0 ;FormStartPosition_Manual
$Form1.Size = $System.Size(240,358) ;(Width,Height)
$Form1.Text = "LAN Messenger"
$Form1.Top = 0

$Label1 = $System.Label()
$Label1.BorderStyle = 0 ;FixedSingle
$Label1.Left = 24
$Label1.Text = "Gebruiker"
$Label1.TextAlign = 16 ;MiddleLeft
$Label1.Top = 19
$Label1.Width = 55
$nul = $Form1.Controls.Add($Label1)

$ComboBox1 = $System.ComboBox()
$ComboBox1.Height = 21
$ComboBox1.ItemHeight = 13
$ComboBox1.Left = 89
$ComboBox1.Text = "Select..."
$ComboBox1.Top = 20
$nul = $Form1.Controls.Add($ComboBox1)

$RichTextBox1 = $System.RichTextBox()
$RichTextBox1.Height = 171
$RichTextBox1.Left = 13
$RichTextBox1.Text = ""
$RichTextBox1.Top = 68
$RichTextBox1.Width = 209
$nul = $Form1.Controls.Add($RichTextBox1)

$TextBox1 = $System.TextBox()
$TextBox1.Height = 61
$TextBox1.Left = 13
$TextBox1.Text = ""
$TextBox1.Top = 258
$TextBox1.Width = 125
$TextBox1.Multiline = -1
$nul = $Form1.Controls.Add($TextBox1)

$Button1 = $System.Button()
$Button1.Height = 61
$Button1.Left = 152
$Button1.Text = "Send!"
$Button1.Top = 258
$Button1.Width = 70
$Button1.Click = "SendMSG()"
$nul = $Form1.Controls.Add($Button1)

$Form1.Show ;Displays the Form
Init()
While $Form1.Visible
$Nul = Execute($Form1.DoEvents())
Loop
Exit 0

Function SendMSG()
Dim $msg, $rcpt, $x
$msg = $TextBox1.Text
$rcpt = $ComboBox1.Text
If $rcpt = "Select..."
$x = MessageBox("You have to select a user first!","Info",0)
Goto "end"
EndIf
$log = $log + @CRLF + "You said to " + $rcpt + ":" + @CRLF + $msg + @CRLF
$RichTextBox1.Text = $log
shell "%comspec% /c net send $rcpt $msg > nul"
$TextBox1.Text = ""
:end
EndFunction

Function CatchMSG()
Dim $sMessageText, $sFrom, $sTo, $sDate, $sTime
If $oAutoIT.WinExists($sMessengerTitle)
$sMessageText=$oAutoIT.ControlGetText("last","",$iControlMessage)
$=$oAutoIt.WinClose("last")
$sMessageText=split($sMessageText,@CRLF)
$sFrom=Split($sMessageText[0]+" ")[2]
$sTo=Split($sMessageText[0]+" ")[4]
$sDate=Split($sMessageText[0]+" ")[6]
$sTime=Split($sMessageText[0]+" ")[7]+" "+Split($sMessageText[0]+" ")[8]
$sMessageText[0]=""
$sMessageText=SubStr(Join($sMessageText,@CRLF),5)
$log = $log + @CRLF + $sFrom + " says to you:" + @CRLF + $sMessageText + @CRLF
$RichTextBox1.Text = $log
EndIf
EndFunction

Function Init()
Dim $Users, $User
$Users = GetObject("WinNT://@ldomain")
$Users.filter = "User",""
For Each $User In $Users
$x = $ComboBox1.Items.Add($User.Name)
Next
EndFunction