Right! You have a mac

(I wish I had one lol)
Textures that are not have the same width as height will not show up for macs!
What you could do is grab the texture, resize it in a paint program to 1024x1024 or 512x512 and use that to import. Important to not keep the original constraints (sp?). And very important to do the alpha's the same way! (black and white files) It should work then
