So you're trying to use a texture you made in the ltm texture editor, it sounds like? If so, make sure you pressed the grey Deploy button at the top of the editor page (the page that you see after editing). If you don't, it won't run. Also make sure you put the texture into a mod, with the correct name on the change texture block. It should be your ltm nickname and the file name, like it shows you on the texture editor page.