WPS54GU2 - no wireless connection

>I wonder if anyone can help, as I'm a bit confused with my new
> wireless print server.
>
> I connected it to the wired LAN to configure it, then disconnected the
> LAN cable and let it loose to run wirelessly.
>
> When I plug the LAN cable in it works okay,  wired and wireless PCs
> can print to it (the wireless PCs are connecting through a D-Link
> AP2100, which is connected to the same LAN as the WPS54GU2.
>
> But with no LAN connected, irt does nothing.
>
> On one of the wireless PCs I installed the print server driver
> software, found the print server (LAN connected) and printed to it.
> But not when the LAN is disconnected.

It sounds like ordinary wireless configuration issues.  Is the print-server
set to infrastructure mode?  Do the WEP settings match those on the AP?

> And on the other PCs I haven't installed this driver, they can still
> print over the LAN, but not wirelessly, of course.
>
> Also, I have powered it down and up between removing the LAN cable and
> trying to use it wirelessly.
>
> If I power it up with the LAN cable in the WLAN LED doesn't light, but
> if I power it up without the LAN connected the WLAN LED does light
> (flickers, actually), but no connection.

This is normal.  You can only have one connection from the print-server to
the the network: either wired or wireless.

> One point I noticed is that there is only 1 IP address. I had expected
> there to be 1 for LAN & 1 for WLAN, so I'm confused by that.

This is normal.  You can only use one of the connection types at a time:
wired or wireless.  So there's no need for two IP addresses.  Even if the
device allowed both connections simultaneously, this isn't a router, so the
connections would be bridged, and only one IP address would be needed.

> So, is it broke or am I doing something wrong?
>
> BTW, the printer is a HP LJ4105 connected through a parallel cable.
>
> Thanks.