using wmi to get username in remote machine

[andres]

i have the following sub running on a small vb.net app,

Private Sub btnGetUserName_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) _
Handles btnGetUserName.Click

Dim objWMIService As Management.ManagementObject
Dim strPath As String = "winmgmts:" & _
"{impersonationLevel=impersonate}\\" & txtComputerName.Text &
"\root\cimv2"

objWMIService = New Management.ManagementObject(strPath)

Dim colComputer As Management.ManagementQuery

'colComputer = New Management.SelectQuery("Select * from
Win32_ComputerSystem")
Dim selectQuery As New SelectQuery("Select * from
Win32_ComputerSystem")

Dim searcher As New ManagementObjectSearcher(selectQuery)

Dim mgmObject As ManagementObject
Dim strUserName As String
Dim strCompName As String

For Each mgmObject In searcher.Get()
strUserName = mgmObject("UserName").ToString()
strCompName = mgmObject("name").ToString

Next mgmObject

lblUserName.Text = strUserName
End Sub

when i try to run the program i get the following error:

An unhandled exception of type 'System.Management.ManagementException'
occurred in system.management.dll

Additional information: Invalid parameter

This error is refering to the line
objWMIService = New Management.ManagementObject(strPath)

it seems that my winmgmts syntax is not correct... but cant figure out what
is wrong with it. Any help would be much appreciated.

Thank you