Special Tiles:Why are all my tiles oddly-colored while playing?

CLUTs control what set of colors are used within a level; mixing-and-matching CLUTs with tilesets can make things look odd.

Find another person's level that uses the same tileset as you. Open the Level Infos in both levels and compare the "Tile/Bkgd CLUT" values. If they are not the same, change your value to match the other.