Ahh, yes - I had forgotten about that -deletemerge command (didn't have my laptop yesterday when I was replying to the post). If the media deleted without being expired, it looks like they had no 'assign' time, and therefore in theory contained no valid images.
You have a choice:
1. Obtain a valid support contract to allow nbcc to be run and properly check the system
2. Upgrade without nbcc - this should not cause an issue in terms of causing an upgrade to fail, it just means any nbcc issues that might be there before the upgrade, will still exist after the upgrade.
M