">>>> error <<<< Internal Error (001) occurred..." seems to be a default that is attached to too many problems.
Recent issue was that you cannot use cross sheet graphics if the Def_sheet_format is protected, even though the graphics do not appear to have any connection with that layer and were not being placed onto it.
The admonition to run the check database routine almost never reports any issues (in this case it was NOT a database issue) and it requires the work to package up enough information for diagnostics and a file a support request for something that a reasonable error message should take care of. The ">>>> error <<<< Internal Error (001) occurred..." message should be reserved for actual corruption of the database or a program error. Anything significant enough to create it, should be considered a programming issue.