Well, the rep using the computer changed the firewall settings to be more secure (not needed since we are already behind our hardware firewalls) and that caused the servers IP block not to be in a trusted zone area.
Once we added the server's IP block to the trusted network, all worked great.
Thanks for the reply.
Some of our clients have reported very strange issues with firewalls etc., but as each firewall is different we haven't been able to solve the problem for all of them.
The RAQ self-signed certs cause problems with ZoneAlarm, while standard https: connections, such as those generated by webmin work fine... very odd