fmPreferences - Table Remapping Menu
For the Store Manager to function properly, some standard shopping cart Database tables (products, orders etc.) are required. To make sure these settings are correct, please go to Tools -> Preferences -> Table remapping and check if all renamed tables can be detected.
To do this simply press [Find renamed tables] and you'll see the list of the default Shopping Cart tables and tables at your store, which correspond to them. You can also manually add or remove the remained tables from the list; however it will not affect the Database tables in any way.
Also if you have renamed some fields there is a possibility that it may not work properly, since there is no way to detect them.
Though Table remapping is much more flexible than Table Prefix, the latter is used as an alternative to the Table remapping in case there is a similar prefix for each table. It's easier to specify this prefix once, than make software look for all remained tables. Table Prefix field can be found in Tools -> Preferences -> Advanced.