.cbr file opening?

i have some .cbr files for a comic book series, "The Maxx" and I cannot open them. i have tried changing the file type to rar, and opening with unrarx, since i use a mac. i tried using Comical, FF, and also i tried opening on a PC, none of which worked. it says the files are corrupted, but i dont believe they are. can anyone suggest what i can do?