Roseward,
Well it can be a few things.
1. The PS-1 is not up and running. Test: ping the IP address of the PS-1 and see if it is up. If it is then use Putty to SSH into it and get to it command console; you will need the database programming password.
2A. SSH has been turned off on either the Base System or the PS-1 database. Get in to database programming of the PS-1 and see if SSH has been turned off. Go to System > IP Settings > Web SSH Settings > SSH Server enabled: Yes
2B. If it is turned on in the PS-1 then look in the Base System by turning off Gateway Mode through the front panel buttons. Center Button once, Down Arrow once [System Settings], Center Button once [Enter System Settings], Down Arrow until you see Gateway Mode, Center Button once [Enter Gateway Mode], Down Arrow once [Set to No], Center Button once [Enter setting], Center Button once [Accept Settings]. Follow these steps again to turn it back on. Then get into database programming and follow steps on 2A; this is most likely not the problem, but I have seen it happen once so I put it in here.
3. The IP addresses of the two systems are not what they think they are. Ping what should be both the base system and the PS-1 to see if they are up and working. You can change the IP Address of the base system through the front panel, but you can only change the IP Address of the PS-1 through the command console if you can't get into database programming with its known IP address. The default IP Address is 192.168.200.201 I believe.
Thanks,
TE