The specified field could not be added to the table. Check below for the solutions to the following conditions:
- The field name is invalid.
- You have another ArcMap or ArcCatalog session that has placed a lock on the table.
- You do not have permission to edit the table.
- Check the field name and make sure it is valid.
- Remove the dataset from any other ArcMap/ArcCatalog sessions that may be accessing it. If necessary, close those other sessions.
- Check that you have permissions to edit the table.