The texture files are saved as dds files. This stands for direct draw surface and it's the internal format used by direct x.
Your art program must support the dds file format or use a plug-in that supports it. For Photoshop you can download a plug-in from nVidia from here.
Paint.NET, a free art program for Windows, also natively supports dds files.
You can also use a stand alone program to convert the file format. One program I'd recommend is the Compressonator. You can get it from here.
thx but i already downloaded it, i didnt have problem to open the original file, i have problem to the saved document, i cant reopen it, and its saved in .tga
and the other thing, i cant repack it.... i think my tools wont work correctly, because the only way i can unpack file by selecting combine option by pressing right click, and if i wanna just run the program i cant, because instantly stop working...