when i download .sis themes and i recive it i cant make it as themes becoz it come like strange text and dont know what to do so how can i have themes in my mobile N6600

if you received the .sis from another cellphone, like by using the seleQ or FExplorer, it will read it as corrupt... however, if you downloaded it from a website or wapsite, well, that's never happened to me before...

hmm so what should i do ? how to have themes in my mobile with wap becoz i dont have bt or infra is there any idea ?