I need help

I want to add a video of a funny fish funnily flopping for a couple seconds each time you get thirsty. I tried doing this, but it seems that using a program to program games on an OS that it technically shouldn't be running on had limitations, and I can't do it since Mac doesn't accept .ogg or .ogv files. I tried converting the videos, and even though it converts, RPG Maker 2003 still will not accept it. Any other RPG Maker 2003 Macbook users who can help me out? Thanks a lot!