Can you please provide us more context? You said it gives an error but it isn't clear what actual error you're getting. It also isn't clear when this macro is supposed to run and whether this is the actual line that is failing or something else. A string assignment shouldn't cause any issues so I suspect it is later.
I'm also confused by the
DBengine reference. In VBA my understanding is this object is for the Access engine but you said you're in word. Can you provide us with what the macro is actually doing?
You mention an error code that seems to be Class Not Registered. That would seem to indicate you're trying to load a COM object (Access?) but it cannot be found. That would happen if you didn't have Access installed or if you had the access runtime installed but it was the x64 version and you're running Office x86, but I didn't think that was allowed by the installer. I could be wrong though.
Temporarily map the Z drive to the correct UNC path. Does it work? If so then this eliminates most everything except security permissions and network issues.