[MajinPenis]

Well, ....

If its made up of many segments (rar-r##) then you should try to unrar them and see on which one the error happens on, then try to re-dl that file and hope it works.
And if its only file then I suggest downloading the whole thing over again, or maybe getting it from somewhere else if you think they might be serving corrupt files.

There is no possible way to fix the "unexpected end of archive" error since if winrar says it is corrupt there is nothing you can really do about it, that file cant be fixed.