Zip code fpo96764 where is this country

iam told this is a us code not vietnam

FPO is Fleet Post Office The Navy Postal System. Part of the Military Postal System

According to this web page: http://freebizadsweb.com/apofpolist.asp That FPO 96764 does not exist.

the zip code 96764 is on hawai'i island, in laupahoehoe.