Running activex dll fromVB6 under windows 7

Question

I'm adding some functionality to an old admin tool written in VB6. The tool uses a c++ activeX object. I haven't worked on the tool since I upgraded to windows 7 and now the active X object fails to load with the 429 "ActiveX component can't create object" error. I'm not knowledgeable about VB6 but I have registered the activex dll and type library and I can remove and add the object from the project via the project->references window (the program fails to compile when the reference is removed as expected). The VB6 ide is running in administrator mode and I get the same error if I run the exe directly as an administrator.

Has anyone else experienced a similar problem and found a way to sort it out?

Thanks, Patrick

PS : I have also tried putting the dll in question in the working directory of the exe

EDIT: I've had no luck trying to sort this out and ended up remoting into a windows 2003 server to test the changes.

Answer 1

You might try using Mark Russinovich's regMon and FileMon to see exactly what files or regkeys are being requested during the load of that dll. That can often tell you if you've got a missing dependency.

Also the DEPENDS.EXE that comes with VS6 is sometimes good for that (though it doesn't necessarily get ALL the dependencies of a dll or exe).

Answer 2

COM is going to use the registry to map from the class name to the physical DLL file that has to be loaded.

Check the registry keys pertaining to your COM object... first under HKEY_CLASSES_ROOT, then the class name, which gets you the CLSID, then the HKEY_CLASSES_ROOT/CLSID section for the GUID of the object, and then see where the physical library lives.

Answer 3

A 429 could mean all sorts of different things. Many times, it means that there's a dependency missing, and the easiest way to figure out what dependency is missing is to use procmon to see what files/registry settings the app is trying to access and hopefully, catch where you get ACCESS_DENIED or FILE_NOT_FOUND or what have you.

Answer 4

The problem might also be with your browser. A couple weeks ago I upgraded my IE, since then I've had to make changes by opening IE, click tools, click custom, scroll to the activeX controls and enable, and/or click prompt. The same was needed for scripting and for me to use XMLHttprequest. Now everything is back to working, however the ActiveX warning alert sometimes takes over 2 minutes to pop-up, then when clicked everything works fine.

Answer 5

Do you have UAC enabled on that machine? Have you tried disabling it? I have seen some cases where it let ActiveX controls being registered but didn't let applications using them ran.