Eu criei um Crystal Report usando o método "pull" para obter dados do SQL Server Express. Eu exporto o relatório para pdf. Funciona bem, mas apenas no pageLoad. Eu recebo esse erro sempre que tento exportar o relatório em um postback.

Failed to open the connection.
Details:  [Database Vendor Code: 4060 ]Failed to open the connection.
CrystalReportPull {2B7D5D2A-C29F-4F27-AFAD-EEAECD909D08}.rpt
Details:  [Database Vendor Code: 4060 ] 
  Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

 Exception Details: System.Runtime.InteropServices.COMException: Failed to open the connection.
Details:  [Database Vendor Code: 4060 ]Failed to open the connection.
CrystalReportPull {2B7D5D2A-C29F-4F27-AFAD-EEAECD909D08}.rpt
Details:  [Database Vendor Code: 4060 ]

Source Error: 

Line 58:                 CrystalTable.ApplyLogOnInfo(logonInfo)
Line 59:             Next
Line 60:             report.ExportToHttpResponse(ExportFormatType.PortableDocFormat, Response, True, "ExportedReport")
Line 61:             report.Dispose()
Line 62:         End If

 Source File:  C:\Users\boruch\Dropbox\Korns-ConnectionStr\reports\CreateReport.aspx.vb    Line:  60 

Stack Trace: 

[COMException (0x800002f4): Failed to open the connection.
Details:  [Database Vendor Code: 4060 ]
Failed to open the connection.
CrystalReportPull {2B7D5D2A-C29F-4F27-AFAD-EEAECD909D08}.rpt
Details:  [Database Vendor Code: 4060 ]]
   CrystalDecisions.ReportAppServer.Controllers.ReportSourceClass.Export(ExportOptions pExportOptions, RequestContext pRequestContext) +0
   CrystalDecisions.ReportSource.EromReportSourceBase.ExportToStream(ExportRequestContext reqContext) +525

[InternalException: Failed to open the connection.
Details:  [Database Vendor Code: 4060 ]
Failed to open the connection.
CrystalReportPull {2B7D5D2A-C29F-4F27-AFAD-EEAECD909D08}.rpt
Details:  [Database Vendor Code: 4060 ]]
   CrystalDecisions.ReportAppServer.ConvertDotNetToErom.ThrowDotNetException(Exception e) +346
   CrystalDecisions.ReportSource.EromReportSourceBase.ExportToStream(ExportRequestContext reqContext) +627
   CrystalDecisions.CrystalReports.Engine.FormatEngine.ExportToStream(ExportRequestContext reqContext) +1203
   CrystalDecisions.CrystalReports.Engine.ReportDocument.ExportToStream(ExportOptions options) +150
   CrystalDecisions.CrystalReports.Engine.ReportDocument.ExportToHttpResponse(ExportOptions options, HttpResponse response, Boolean asAttachment, String attachmentName) +211
   CrystalDecisions.CrystalReports.Engine.ReportDocument.ExportToHttpResponse(ExportFormatType formatType, HttpResponse response, Boolean asAttachment, String attachmentName) +240
   reports_CreateReport.Page_SaveStateComplete(Object sender, EventArgs e) in C:\Users\boruch\Dropbox\Korns-ConnectionStr\reports\CreateReport.aspx.vb:60
   System.Web.UI.Page.OnSaveStateComplete(EventArgs e) +9644490
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1282

Aqui está o meu código em vb.net:

txt_from.Text = Now.Date.AddYears(-1)
        txt_to.Text = Now.Date
        If IsPostBack Then
            Dim report As New ReportDocument()
            report.Load(Server.MapPath("~/reports/CrystalReportPull.rpt"), OpenReportMethod.OpenReportByTempCopy)
            Dim custID As Integer = -1
            If ddl_Customer.SelectedValue <> "" Then
                custID = CInt(ddl_Customer.SelectedValue)

            End If
            report.SetParameterValue(0, txt_from.Text)
            report.SetParameterValue(1, txt_to.Text)
            report.SetParameterValue(2, custID)


            Dim logonInfo As New CrystalDecisions.Shared.TableLogOnInfo()
            Dim CrystalTable As CrystalDecisions.CrystalReports.Engine.Table
            For Each CrystalTable In report.Database.Tables
                logonInfo = CrystalTable.LogOnInfo
                logonInfo.ConnectionInfo.ServerName = "BORUCH-PC\SQLEXPRESS"
                logonInfo.ConnectionInfo.DatabaseName = ""
                logonInfo.ConnectionInfo.UserID = ""
                logonInfo.ConnectionInfo.Password = ""

                CrystalTable.ApplyLogOnInfo(logonInfo)
            Next
            report.ExportToHttpResponse(ExportFormatType.PortableDocFormat, Response, True, "ExportedReport")
            report.Dispose()
        End If

Eu recebo o mesmo erro quando eu executo este código em um clique de botão, ou mesmo em pageload se eu envolver em umif ispostback cláusula.

Eu tentei executar este código no prerender, init etc ... sem sucesso.

Crystal Reports versão 13.0, .NET 3.5, SQL Server 2008 Express, VS 2010

Qualquer ajuda seria muito apreciada.