If you have the par files that could have been created based on the file that was rared, then the answer is "most likely yes."
If there are par files, then you need to look at macpar deluxe.
If there are not any par files available, then your out of luck. Unless the error is referring to an incomplete download of one of the rar files. Then it is possible to redownload the bad files, and try to unrar it again.