.NET with Navision 3.70B

Hi, I have one intresting problem when I tried to integrate my DOT NET DLL winform application to Navision 3.70. I have created a WinForm application in .NET and made it available as interop to Navision. I have added the DLL to Navision using Automation object. I created the object using CAL Code and tried to open the form when a menu is clicked. It works perfectly with Navision 4.0 and failed with Navision 3.70B. My question is whether earlier versions of Navision 4.0 won’t support Automation feature with .NET DLL’s. Can anyone help me out to solve the problem? Thanks in advance. :smiley: