Problem solved. I re-read the Installation Guide and found this:
"Important Installation Notes for NAC-3310
When following the CD-ROM system software installation procedures above and installing release 4.0(x) on a NAC-3310 appliance (both MANAGER and SERVER) from a CD-ROM, you are presented with the following prompt during the installation process:
Cisco Clean Access 4.1-1 Installer (C) 2007 Cisco Systems, Inc.
Welcome to the Cisco Clean Access 4.1-1 Installer!
- To install a Cisco Clean Access device, press the key.
- To install a Cisco Clean Access device over a serial console, enter serial at the boot prompt and press the key.
boot:
The standard procedure asks you to press âEnterâ or, if installing via serial console connection, enter serial at the boot: prompt, For release 4.0(x), however, NAC-3310 customers are required enter one of the following, instead:
â¢DL140-if you are directly connected (monitor, keyboard, and mouse) to the NAC-3310
â¢serial_DL140-if you are installing the software via serial console connection
After you enter either of these commands, the Package Group Selection screen appears where you can then specify whether you are setting up a Clean Access Manager or Clean Access Server and install the system software following the standard installation process."