I am receiving the following exception randomly when printing crystal reports
via a
print server application.  The server will successfullky print a random
number of identical files and then for some reason, the following exception
is logged.

System.InvalidOperationException: Stack empty.
  at System.Collections.Stack.Pop()
  at SCRStartup.Leave()
  at CrystalDecisions.CrystalReports.Engine.ReportObjects..ctor(SCRPrintJob
printJob, Int32 sectionCode)
  at CrystalDecisions.CrystalReports.Engine.ReportObjects.GetEnumerator()
  clsReports.LogInReport()

The code for LogInReport is as follows

       Dim ret As Boolean = False
       Dim repDoc As New ReportDocument
       Dim subRepDoc As New ReportDocument
       Dim crSections As Sections
       Dim crSection As Section
       Dim crReportObjects As ReportObjects
       Dim crReportObject As ReportObject
       Dim crSubReportObject As SubreportObject
       Dim crDatabase As Database
       Dim crTables As Tables
       Dim crTable As Table
       Dim crConnInfo As New ConnectionInfo
       Dim crLogOnInfo As New TableLogOnInfo
       Try
           repDoc.Load(mstrFile, OpenReportMethod.OpenReportByDefault)

           With crConnInfo
               .ServerName = mstrServer
               .DatabaseName = mstrDatabase
               .UserID = mstrUserName
               .Password = mstrPassWord
           End With

           'we iterate through the report database tables and log the user in
           crDatabase = repDoc.Database
           crTables = crDatabase.Tables
           For Each crTable In crTables
               crLogOnInfo = crTable.LogOnInfo
               crLogOnInfo.ConnectionInfo = crConnInfo
               crTable.ApplyLogOnInfo(crLogOnInfo)
           Next

           crSections = repDoc.ReportDefinition.Sections
           For Each crSection In crSections
               crReportObjects = crSection.ReportObjects
               For Each crReportObject In crReportObjects
                   If crReportObject.Kind =
ReportObjectKind.SubreportObject Then
                       crSubReportObject = CType(crReportObject,
SubreportObject)
                       subRepDoc =
crSubReportObject.OpenSubreport(crSubReportObject.SubreportName)
                       crDatabase = subRepDoc.Database
                       crTables = crDatabase.Tables
                       For Each crTable In crTables
                           crLogOnInfo = crTable.LogOnInfo
                           crTable.LogOnInfo.ConnectionInfo = crConnInfo
                           crTable.ApplyLogOnInfo(crTable.LogOnInfo)
                       Next
                   End If
               Next
           Next
           ret = True
       Catch ex As Exception
           EventLog.WriteEntry(AppName, ex.ToString, EventLogEntryType.Error)
       End Try
       Return ret

Any ideas?

TIA