HaloMods "Classic" Read-only Archive

i downloaded PS, and .dds but when i try to open a texture my friend sent me (cause when i try to open HMT it doesnt work (look in the HMT forum if u can answer that)) i put the dds plugin in the right folders but when i try to open them PS says this is not the right file u cannot view this. or somthing like that, any thing i can do

same thing happened to me
its just that the plugin is either in the wrong place or PS didnt accept it
what i did to fix it was reinstall PS and get the plugin again and it works
about the HMT problem ill go there now and see wut i can do