I still cannot install any themes on my 7250

I cant understand it, Im def a newb to this so please bear with me. IT says they are not blocking any applications. I had it once before, my counterpart had loaded themes on my 7250 but I remmember he had to hack some file or something?? I dont remmember:( Everytime I try to load the .alx file thru appl loader, it says it goes through fine BUT when I go to options\themes its not there.. I have the latest desktop manager, etc. I am so frusterated, please help!!:(:( I cant stand the default theme!