vb.net and background worker for system uptime

I am attempting to write a small amount of code to return to me the system uptime of a remote workstation.  It works when ran directly from a button, but when i try to put it in a background thread it fails everytime.

Below is the code i am using:

Private Sub BackgroundWorker1_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
        Dim worker As BackgroundWorker = CType(sender, BackgroundWorker)
        Try
            Dim str_ServerName As String = TextBox1.Text
            Dim pc As New PerformanceCounter("System", "System Up Time", "", str_ServerName)
            pc.NextValue()
            Dim ts As TimeSpan = TimeSpan.FromSeconds(pc.NextValue)
            MsgBox(str_ServerName & " has been up for " & ts.Days & " days, " & ts.Hours & " hours, " & ts.Minutes & " minutes, " & " and " & ts.Seconds & " seconds.", , "System Uptime")
        Catch ex As Exception
            MsgBox("Workstation Uptime not found", MsgBoxStyle.Information, "Information")
        End Try
    End Sub

    Private Sub BackgroundWorker1_ProgressChanged(sender As Object, e As System.ComponentModel.ProgressChangedEventArgs) Handles BackgroundWorker1.ProgressChanged

    End Sub

    Private Sub BackgroundWorker1_RunWorkerCompleted(sender As Object, e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted
        If e.Cancelled = True Then
        End If
    End Sub

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I declare the below:

Private bw As BackgroundWorker = New BackgroundWorker
    Public Sub New()
        InitializeComponent()
        bw.WorkerReportsProgress = True
        bw.WorkerSupportsCancellation = True
        AddHandler bw.DoWork, AddressOf BackgroundWorker1_DoWork
        AddHandler bw.ProgressChanged, AddressOf BackgroundWorker1_ProgressChanged
        AddHandler bw.RunWorkerCompleted, AddressOf BackgroundWorker1_RunWorkerCompleted
    End Sub

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I then try to run the method from a button:

  If Not bw.IsBusy = True Then
            bw.RunWorkerAsync()
        End If

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What am i doing wrong?