Auto-Protect could not load scan engine

I'm getting the "Auto-Protect could not load scan engine" error message--on a 2012 Mac Mini running 10.7.4. This was running fine for about 4 months and then got this error. All the other computers setup in this lab at the same time are still running okay. 

 

Here is the catch - this is a classified computer and there is no internet connection and never will be. All patches and updates are installed manually.

 

I've used the uninstall script twice and reinstalled with no success. I've tried versions 12.2 and 12.3. I've also tried the keychain trick to get it to prompt for the activation key and it does not. Very frustrating. If this software doesn't work I'm going to have to replace it on 10 of these classified computers. I wouldn't have even used Norton (knowing this software is heavy and a burden) but the stupid guberment requires this or McAfee which just might be worse if thats hard to believe.