FRP is one of the common TLA's (Three Letter Acroynms) for the Fantasy
Role-Playing hobby, usually meaning Fantasy games of the group first popularized
by D&D but often used as a shorthand for the entire role-playing gaming command.
The AD&D is indeed the TSR gaming product; AD_D is a rogue like game which
was designed to be more AD&D-like. I haven't gotten my copy yet so I can not
give more details.