just got this random error playing someones custom map and since im starting to map myself id like to know how to fix it in the future. no idea if the img tags work  ,so heres a link to the picture

To use the Image tags, you have to include a direct link to nothing but the image. This is the right link - http://image.prntscr.com/image/3a6c5ffc660a4254b5aee3c32901db8a.png