Karen,
I appreciate the quandry you are in by having to back fill a position you have limited experience of.
So you are on a closed network that presumably has no connection to either the internet or to any other networks in your company, and things worked previously but now something has changed and things have stopped working. So something has changed during the time you were working on other problems and whatever this change is, it is stopping Ghost console from working.
The time you took off to investigate network connection problems - were they on this closed network or elsewhere?
I am curious about the converter boxes that link your machines to your network - how are they connected to your machines? Are they plugged into a USB port ? It is important that we understand how your network is put together as Ghost console relies on the network environment. What is the role of the router on your network? You say it is the other side of the server from the workstations, but if this is a closed network, what is it's actual role? Are your machines linked to your server by a switch, to which the router is also connected? If so, does unplugging the router make any difference to your problem? Do your machines have static IP addresses or do they get their IP addresses from a DHCP server.
Are you able to "Ping" your server from the workstations? (Go to command prompt and type PING followed by a space and then the server name or the server IP address)
If you go to the command prompt of each workstation and type IPCONFIG /ALL, are the IP addresses consistent with the server and are the subnet masks and default gateways the same for all machines?
If this problem is business critical to you, now may be a good time to flag up to your management that this issue may require a skill set that is outside your current experience to resolve, and see whether they can offer you a plan B to fall back on. You don't mention whether your manning shortfalls are due to lack of funding or lack of suitable candidates, but clearly you are in an exposed position at the moment.
When you boot your machine from the Ghost boot media - do you get a Vista-like status bar at the bottom of the page as the boot system loads?