Ok, I realize this machine is already EOL, but if anyone else runs into this issue, I found the answer here
- Press the "Utility" button
- Press the "Access" button
- Press * four times
- Press the "Maint" soft button on the touch screen
- Press the "Service Mode" soft button on the touch screen
Once you are in there, you can reset the admin password by pressing the "Administrator # Initialize" soft button, and that will reset the admin password back to the default 00000000. Evidently, this works for a few other models of NEC copiers as well.