I have a user that gets two instances of the "AutoCAD 2011 Type Library" in his VBA references ... both are checked ... one says Missing: the other does not.
If he unchecks the "Missing:" one, then he is fine.
This happnes every time I update a .dvb file on his system. I have tried unloading the .dvb first then reloading but still the same problem.
He is running AutoCAD Electrical 2011. His OS is Windows XP (32 bit).
I am developing the .dvb on AutoCAD 2011 (not electrical) in WIndows 7 (64 bit).
I have a very similar issue and it does appear to be a problem between Windows 32 and 64 bit environments. I'm hoping that maybe you had come up with a solution to the problem as I am yet to find one and googling has only brought me here to your request that nobody seemed to answer.
Reason is, that there is no VBA for 64bit available from Microsoft, they did it just for 32bit and say if you have 64bit change to .NET platform and that's it.
Autodesk did now a trick to have it at least working, the create a separate 32bit-process doing the VBA-job and from 64bit-AutoCAD it sends all traffic through the operating-system to the 32bit-VBA, and every request from the VBA-process to any AutoCAD-geometry/variables/properties.... are also sent from the 32bit-process via operating-system to AutoCAD.
And this why you take one of the type library is missing. Unfortunately there is no solution for that because there is different libraries we talk about like "AutoCAD 2011 Type Library" and "AutoCAD 2010 Type Library".