I am using VB.Net (2.0) to automate MS-Excel.

In the Class, I decla
Private oXL As Microsoft.Office.Interop.Excel.Application = Nothing
Private oWB As Microsoft.Office.Interop.Excel.Workbook = Nothing
Private oWS As Microsoft.Office.Interop.Excel.Worksheet = Nothing


I open the WorkBook when I get an instance of this class:

Public Sub New(Optional ByVal SourceFile As String = "", Optional ByVal
ActivateWorkSheetNamed As String = "", Optional ByVal SetVisible As Boolean =
False)

oXL = New Microsoft.Office.Interop.Excel.Application
oXL.DisplayAlerts = SetVisible
oXL.Visible = SetVisible

If (SourceFile.Trim.Length 0) Then
If File.Exists(SourceFile) Then
oWB = oXL.Workbooks.Open(SourceFile, False, False)
Else
If oXL.Workbooks.Count < 1 Then
oWB = oXL.Workbooks.Add()
ElseIf oXL.Workbooks.Count = 1 Then
oWB = oXL.Workbooks(1)
End If
oXL.SaveWorkspace(SourceFile)
End If
End If

If (oXL.Workbooks.Count < 1) Then
oXL.Workbooks.Add()
oWB = oXL.Workbooks(1)
End If

oWS = oWB.ActiveSheet

If ActivateWorkSheetNamed.Trim.Length 0 Then
Dim I As Integer = 1
For I = 1 To oWB.Worksheets.Count
If oWB.Worksheets(I).Name.ToString.ToUpper =
ActivateWorkSheetNamed.ToUpper Then
oWS = oWB.Worksheets(ActivateWorkSheetNamed)
End If
Next
End If
End Sub

I am getting the above error when calling the following code from my
application, at the line with "-":

Public Function WorkBookExists(ByVal WorkBookName As String) As Boolean
Dim I As Integer = 0
WorkBookExists = False
- For Each oWB In oXL.Workbooks
If (WorkBookName.Trim.ToUpper = oWB.Name.Trim.ToUpper) Then
WorkBookExists = True
Exit For
End If
Next
End Function

Any help would be greatly appreciated.