if you still have the downloaded files , check the file sizes .. only the last should be different. Upgrade your winrar to the latest version and try again. Old versions of winrar can cause errors.
If you think you have bad rars and if you downloaded by torrent delete the bad file/files and restart the torrent and that way you wil only have to download the bad rars
I looked up "gormless" in the dictionary, it said "without gorm" .... so i looked up "gorm" but it wasn't there ????