by Peter Carpenter.
Alrighty, I've gotten the course to restore. The TL;DR of what I ended up doing was just... deleting problematic date from the backup, repackaging it, and trying again. I ended up with 6 users that had duplicate usernames, which I ended up deleting from users.xml in the root of the backup. Next, I had one user that was perfectly fine, but had a number of issues with their completion/scorm entries. This user was the cause of the error. I ended up looking for that specific timecreated stamp in all files within the backup, and found it in the completion.xml file in the root of the backup. I removed that, and ran it again, but got the same error with different values (albeit for the same user as before). Did the search again, and found the issue under activities/scorm_3/completion.xml. Deleted THAT chunk, saved and repackaged the backup, and it worked. I should mention that all the bits I deleted seemed like... nothing values. Grade entries that were null, for instance. Just keep track of what you remove, just in case you want to manually add it back after the restore is done.