Are you using the Instant AOL or other OS ?? It is my understanding you need to run software from AOL on a second computer to "bridge" your AOL accoount to the GCT, I am pretty sure you can't connect directly to the net with the GCT by placing it on a ethernet network. Search for the tread, there was a post sometime ago about that, use "AOL software" as a term.
Now if you have installed a different ethernet card than what the GCT came with this might a problem too, The 10/100 ethernet card that came with the GCT connected directly to the RG45 port without using any connecter, nor did it have any software controlled options to change such (I would guess that this is a normal way to do this, I had a IBM notebook and currently have a Gateway Solo notebook that they all have mini-pci and use this method),
The HPNA mini-pci card uses a two pin connecter to connect to the pins 2 & 3 of of the telephone RG11 port. (both 2 pin conecters on the GCT mainboard are the same, they are wired in series).
There is a four pin connecter next to the 2 other RG11 telephone ports that connects to the RG45 8 conducter ethernet port(ethernet technically just need those 4 out of 8 to cominicate), this should be were you should connect a ethernet card that doesn't support the direct internal network connecter and has a wired connecter to run to the RG45 port.
FYI - The orinal HPNA card and modem that came with the GCT used the very same RG11 telephone lines (2 & 3), the HPNA Mini-pCi card actually was a software 56k modem too, so the HPNA version of the GCT actually have two modems in them, that's why there are two RG11 connecters on the mainboard. One modem was the hardware modem (little rectangle card w/t 4 screws) and the other software controlled one in the combo HPNA/56k modem. It's my belief that second real modem is used with Instant AOL because the Midora Linux didn't have a driver written for the modem 56k function of the combo card.
Does this help??