Automatically Update External Links To Csv File In 2007

I have an Excel 2003 workbook (named TargetWorkbook.xls) with some links to a CSV file called DataSource.csv. I use Excel 2007 to open the workbook. I checked the "Update links to other documents" option under the "When Calculating this workbook..." section on the Advanced pane of the Excel Options window. I unchecked the "Ask to update automatic links" option under the "General" section on the Advanced pane of the Excel Options window. I selected the "Don't display the alert and update links" option on the Startup Prompt dialog (accessed from the Edit Links dialog) I created a simple Auto_Open macro with the following statements:

Sub Auto_Open()
Workbooks.Open Filename:="C:ProjectsExcelTestDataSource.csv", ReadOnly:=True
Worksheets("DataSource").Activate
Workbooks("TargetWorkbook.xls").Activate
Windows("DataSource.csv").Visible = xlVeryHiidden
End Sub

The DataSource.csv file is updated daily. I want the cells of TargetWorkbook.xls to automatically update from the csv file when I open TargetWorkbooks.xls without displaying a prompt. I plan to deploy this workbook to a server and open it programatically via a Windows Service (I know, I know, Microsoft doesn't encourage this)and can't have it throwing up a user dialog.

Here is the problem: When I open TargetWorkbook.xls manually using Excel 2007, it updates the links but throws up the dialog "This workbook contains one or more links that cannot be updated...". When I click on the "Edit Links..." button, it displays the message "Warning: Open source to update values". When I click the "Check status" button for this link, it says "Source is open". How do I prevent this dialog box from poping up? I've been wrestling with this for a few
days now and can't find a solution.