An unknown error occurred while processing the request on the server I have an asp.net 4.0 application with a button that opens a SSRS report.  This works fine on my development machine and I can open the report directly with report manager but when I try to access the report on the production machine I get this error

Webpage error details
User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; Trident/4.0; GTB7.4; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; CMDTDF; BRI/1; .NET4.0C; InfoPath.3; .NET4.0E)
Timestamp: Sat, 1 Dec 2012 21:35:46 UTC

Message: Sys.WebForms.PageRequestManagerServerErrorException: An unknown error occurred while processing the request on the server. The status code returned from the server was: 500
Line: 2
Char: 74741
Code: 0
URI: http://intranet/webapps/TestRecordedOnlyIncidents/ScriptResource.axd?d=ZBsMSL9jIyW8I9p1LwFOBagb0X-bFxrU28WowdY5TbC9ZankzHyooPpti5W0JT6DLsOOmhf_2t5kU1g4r1F40RiMcHtiuYqff50r1VaQMwtZ9CW6zRVLnDMJYHiVvrNZ0&amp;t=ffffffffbad362a4


I've searched the web for a solution and have found a half a dozen but none have worked for me.  Here is my code:

    Dim r = New ServerReport
    r.ReportServerUrl = New Uri("http://vm-intranet/ReportServer")
    r.ReportPath = "/RecordedOnlyIncidents/Reports/AllIncidentsWithParameters"
    Dim EmployeeNumber As String = IIf(txtSearchEmployeeNumber.Text = "", Nothing, txtSearchEmployeeNumber.Text)
    Dim IncidentType As String = IIf(ddlSearchIncidentType.SelectedItem.Text = "", Nothing, ddlSearchIncidentType.SelectedItem.Text)
    Dim BeginningDate As String = IIf(txtBeginningDate.Text = "", Nothing, txtBeginningDate.Text)
    Dim EndingDate As String = IIf(txtEndingDate.Text = "", Nothing, txtEndingDate.Text)
    Dim parmEmpNumEmployeeNumber As New ReportParameter("EmployeeNumber", EmployeeNumber)
    Dim parmIncidentType As New ReportParameter("IncidentType", IncidentType)
    Dim parmBeginningDate As New ReportParameter("BeginningDate", BeginningDate)
    Dim parmEndingDate As New ReportParameter("EndingDate", EndingDate)
    Dim parameters(3) As ReportParameter
    parameters(0) = parmEmpNumEmployeeNumber
    parameters(1) = parmIncidentType
    parameters(2) = parmBeginningDate
    parameters(3) = parmEndingDate
    r.SetParameters(parameters)
    Dim warnings As Warning() = Nothing
    Dim streamids As String() = Nothing
    Dim mimeType As String = Nothing
    Dim encoding As String = Nothing
    Dim extension As String = Nothing

    Dim reportOutput As Byte() = r.Render("PDF", Nothing, mimeType, encoding, extension, streamids, warnings)
    Dim path As String = System.AppDomain.CurrentDomain.BaseDirectory
    Dim stream As New IO.FileStream(path &amp; "/MyReport.pdf", IO.FileMode.Create)
    stream.Write(reportOutput, 0, reportOutput.Length)
    stream.Close()
    Dim Script As String = "&lt;script type='text/javascript'&gt; win=window.open("""",""_blank"",""resizable=Yes,height=600"");win=win.document;win.write(""&lt;style&gt;body{margin:0px;}&lt;/style&gt;"");win.write(""&lt;title&gt; Incidents Report&lt;/title&gt;"");win.write(""&lt;iframe src='MyReport.pdf' style='width:100%;height:100%;'&gt;&lt;/iframe&gt;"");&lt;/script&gt;"
    ScriptManager.RegisterStartupScript(Me, Me.GetType(), "OpenReport", Script, False)


Any suggestions would be greatly appreciated.
I found the answer, the wrong version of the Report Viewer was installed on the server.