dopuslib.dll is part of Opus, and you will break parts of Opus if you unregister it. I can't tell you more specifically what it does, because it does a lot of things. It's like dopus.exe; it is Opus. Various code which is used both inside and outside of Opus lives in that DLL. You should re-register it to avoid problems.
As you might guess from the name, DummyDllFunctionToAviodSymbolConfusion is not a a real function. If you don't have any debug symbols for a DLL (and from your screenshot, you don't have any debug symbols for any of the DLLs including the Windows ones), process monitor picks the name of the nearest named function it can find (if there are any at all), which is usually miles away from the actual code being executed. So we put a dummy function name in a few places to avoid a real, but unrelated, function name being used. The name explicitly says it's not a real function (and you can see the offset after the function name is a large number of bytes, while the dummy function is only a few bytes long).
I'm not convinced dopuslib.dll is the problem from your screenshot. That's probably just showing the thread was started with a dopuslib.dll function (which is normal). You need to expand the branch further to see what code it's actually executing.
Crash, exit or high CPU when viewing certain directories is the guide you want to follow to diagnose the problem.