The Run Time Package is a set of default sprites and Facesets and other graphics that come with RPG maker. These come right with the rpg maker program itself, So there are two ways to fix this:
(Oh, uh before you do this, make sure you know which program was used to make the game. i.e. 2003, 2000, xp, vx...)
You can download RPG Maker, and which comes with the files so no problem!
Or, you could google rpg maker RTP, and the program should be among the results.(NOTE: MOST RTPS CAN BE FOUND HERE ON CRANKEYE, AND FOR XP AND VX WHEN YOU INSTALL THE PROGRAMS THERE IS A SEPRATE OPTION FOR RTP IN THE AUTORUN.)
So uh...that's it.