Before making any changes, make sure you have a system/database backup so that it can be restored in the event there are major errors. Anytime you work with table definitions/changes, there exists the possibility of data loss.
Before setting the new table definitions, have all users out of the system, then do a convert to runtime with wide open range to make sure all existing pending changes (such as those from PMC solutions) have been completed. Then log out and back in.
Then define your new table and references and convert to runtime again so we know it is just these new changes being converted. You will want to convert at the very least both the new table and tccom001, but ideally open range again.
If you do get errors when converting to runtime, stop working with the runtimes and stop trying again. (call Infor immediately. If you run convert again after the failure, you could overwrite the log files and prevent us from debugging the error.)
If you have no Infor support, and still get errors when converting to runtime failed many times, you should restore the system/database immediately.