Unpack an exe

[rilley]

Hy i probably think that, the exe what i`ll attached is packed, and i can not modified in peexplorer,(ex: if i try to open the file in pe explorer and save it the code is different from the original and it doesn`t run..) my question is are there some ways to unpack this file? or can anybody help me to unpack this file? please

File attached..
http://rapidshare.com/files/136617731/PaiNRAT.rar.html