If you open Terminal.app, what names (if any) do you get from running either of these commands?
hostname scutil --get HostName
I have seen my machine change its name to the result of a reverse lookup on a new IP, regardless of what I have set in the sharing preferences. This only happens when the system configuration value for HostName is not set (the result of the second command above). You can use:
sudo scutil --set HostName CR302-04
to set this. You could also confirm and correct the reverse lookup for the IP that machine is using.
After that, you will want to change the name in the Pharos Administrator, and reboot the client. If you do this before installing the SignUp Client, the Setup Assistant should use the right name to register.