Hopefully I should be able to help you out!
Is that supposed to be a map that you may have downloaded? Make sure you have all the textures and code with the map. Make sure you havent made any new typo's in the original file. Make sure the coding matches the exact name of the file. If a texture appears yellow and black, Its the game trying to search for the etxture file that doesnt exist, so it usally goes that black and yellow. Check the material code and make sure their arent any typos in the code lines and they should all match up ^^