In this case, something is locking your files, that error is specifically related to "access denied" when saving the initial render. If you change the save file location, and it saves, then you will want to check into the settings in your "Time Capsule" and Antivirus programs as these would be causing the files to be locked when you try to write to them. As for the subscription, I can send a note up the chain here to the moderators, but we who answer questions are like you, users of the system. We have been vetted and our credentials checked throughly, but we do not control the system. I can assure you; however, that you are only paying for a single question to be answered, and though that is the case, we can speak back and forth here as much as you need to. Please let me know if you need anything further! :)
Nothing to the drive specifically. You do want to adjust your antivirus settings, and time capsule settings as it was doing a scan or backing up on the drive you were using, I set my scan times on my Mac to 3:00am to avoid these strange issues, but it is not a major problem, just a functional glitch. You can always set backups to manual, and if the problem persists you may have to fix permissions, and please let me know if you need the directions for that process!