So clearly, the code is not the problem, just one or more DLL aren't registered.
The version of SolidWorks I am using is actually an OEM version of SolidWorks that comes packaged with OptisWorks 2013 64bit. I understand from the information I gathered that there are a few hoops to jump through when trying to work with x64 machines, and I have setup my VS projects accordingly, but it still doesn't work.
It seems I would have to manually register some DLLs with regsvr32, but which one(s)? All of them? There are quite a few. But even that fails: I have tried to register the file solidworks.interop.sldworks.dll, but it complains that 'the entry-point DLLRegisterServer was not found'.
I have always progammed in linux environments before, I am not very familiar with the inner workings of windows yet.