Everything was running fine but now new installs of clients are failing to register in the management zone.

We are using 10.1 and if I try to do a zac reg I get:

Sucessfully registered with zone "[could not determine]" at url "http://servername.domainname"

Attached is one of the log files.

We are using a mix of Windows XP SP2 and SP3 machines and i have tried recreating the installation packages.