I've had this happen and never found a good answer. I had to restart my drawing from scratch, I'm sad to say. I suspect it had something to do with sheet set manager, but couldn't verify.
I have seen others during my AU lab get the same error, but I have not been able to reproduce the situation that produces the issue.
I would suggest opening a support request. In the request, we will likely need to know what other Autodesk software is installed to determine what is causing the conflict and error message.
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