Naomi, unless something has changed with turnitin, backup and restore is not supported for Turnitin due to how they manage their assignment names, the copy actually is trying to recreate the same TII assignments rather than new assignments.
To work around this issue we recreate every TII assignment used in our courses if/when copies are made.
It's unfortunate, time consuming, but the workaround has worked for us.
If you find out differently from Turnitin please share that information here.
-Joe
