AutoCAD DocumentManager Problems

[jsurpless]

Hi everyone

I'm really hoping that someone can help me out with this...

Imports Autodesk.AutoCAD.Runtime
Imports Autodesk.AutoCAD.ApplicationServices

Public Class Form1

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Dim file As Autodesk.AutoCAD.ApplicationServices.Document

        file = Autodesk.AutoCAD.ApplicationServices.Application.DocumentManager.Open("D:\Somefile.dwg", True)

    End Sub

End Class

This is just a sample of the code I'm having a problem with... it seems that whenever I do *anything* with the DocumentManager, I get strange errors that don't seem to make much sense... for instance, here... I get a FileNotFoundException before it even processes the Dim statement...

Any help would be *most* appreciated...

Thanks!