REACH'S PROFILE

Recently I've been trying to edit textures from rm chipset and have finally figured out how to do it without getting the "Unsupported PNG Image! Make sure you are using a colour depth of 8 bit (256 colours)" message when trying to load it in rm but now whenever i try to test the game it just says "Unsupported PNG"

Does anyone know how to fix this problem without having to change what I've done to the textures?

p.s. I'm also a noob at this so please explain in noob language