I think there were a couple versions of FF2 US released.
The program is probably looking for a specific version (1.0 or 1.1).
Google search the GoodTools name ("Final Fantasy II (U) (V1.0)") and you should quickly find both versions of the ROM.
Ehh... Kinda stupid question but... What is GoodTools and i googled 'GoodTools name ("Final Fantasy II (U) (V1.0)' and 'Final Fantasy II (U) (V1.0)' but nothing was founded.
Good Tools is a series of programs (in this case, GoodSNES) designed to detect and automatically rename ROMs for a corresponding system.
While the accuracy of the program has been debated plenty, it is important because presently, most ROM sites will upload all ROMs for supported consoles, and distribute them using GoodSNES to name the files.
(though perhaps I should have just said to check the "Where to find ROMs" topic stickied in the General Discussion forum, instead of Google.)