TV Episode Will Not Download

I have purchased a boxset and when reviewing its download to my computer, I noticed one episode was missing. I confirmed in the iTunes store under "Purchased/Not on This Computer" that it was outstanding. I attempted to download it but received an error--ERR = 500. I have rebooted iTunes, my computer, &tc, however, I keep receiving the same error or the Internal Server Error. The drive it is being downloaded to has over 7 TB of free space. The error comes immediately, there is no attempt to download anything first. The other 200+ episodes of the series downloaded fine. Any ideas?