.NET 4 - Could not load Interop.SymBBAuto - Mech 2012 64 bit

[Anonymous]

I originally posted this in the Mechanical discussion group by mistake.

In VB.NET for AutoCAD Mechanical 2012, 64 bit, Windows 7 using Visual Studio 2010 Pro .NET Framework 4.0, I get "Could not load file or assembly 'Interop.SymBBAuto, Version=2.0.0.0, ...".  Mechanical is started by running debug.  The .dll has been loaded.  When I issue the custom command the program halts at the point where the program is calling a sub routine that contains 

Dim SymBB As McadSymbolBBMgr = CType(AcadDoc.Application.GetInterfaceObject("SymBBAuto.McadSymbolBBMgr"), McadSymbolBBMgr)

Autodesk SymBBAuto 3.0 TypeLibrary is referenced along with the other necessary libraries.

If I do my work under .NET 3.5 I do not get this error.  However, under .NET 3.5 I do not get 'live' debugging.

Is there some issue with SymBBAuto in Mechanical 2012 and .NET Framework 4.0?

[Anonymous]

Did you ever figure this out?  I'm having the same results.

[Anonymous]

Farren,

No I have not, and apparently there is very little Autodesk .NET support for those of us working in Mechanical.

I am currently working on this program under .NET 3.5 without the ability to debug.  This is my first major attempt at .NET and have found that it is not quite as simple as some would have you believe.  I currently have a number of VBA programs that I need to migrate to .NET before we upgrade to 2012 and Windows 7 on 64-bit machines.  Based on testing, some of those VBA programs will not work correctly on the new machines and the one I am attempting to re-write is the most critical.  I extract Mechanical BOM data and export it to a Bill of Material workbook in Excel which is why I need SymBBAuto.

I am finally at a point where the program will run one-time-through.  But if I open a second drawing and try running the program again I get a fatal error.  I also have found that there is an instance of Excel.exe running in the background for each time I have run the program even though I have manually closed Excel each time.  I do not close Excel through the program because the drafter needs to do some additional work in the Excel BOM before it is printed.  I have used .Dispose on objects and have set them and any collections = to Nothing.  I must be missing something somewhere, but without the ability to use debug, it isn't easy to find.