I would also test the value returned by the call to Fill on your table adapter. If it is zero then no records are being retrieved, which is a different problem to records being retrieved but not displayed.

Also, are you calling Fill in the Load event handler? If so then maybe an exception is being thrown, but it would be swallowed in that case. You might try adding an exception handler to your Load event handler to see if that's the case, e.g.
Code:
Try
    'your code here
Catch ex As Exception
    MessageBox.Show(ex.ToString())
End Try