Error in retrieving tables / object already exists (UNV0035)

In XiR2 Designer we are usually able to invoke the table browser without issue, however after working in the app for some time... when invoking the table browser the error msg "Error in retrieving tables / This object already exists. (UNV0035)" pops up. Then you are still able to open the table browser. I've seen the same or similar msg when trying to insert or edit derived tables. As mentioned, usually the table browser functions ok, so the db rights seem in order. Has anyone else experienced / solved this?

-Bob