Cable Modem to Wireless part 2

[updater]

The set is as follows.
Fibre VM cable from street to box on wall outside the house.
Inside the house a white Coax cable comes out of the box on the inside of the house.
This goes to a splitter, one cable goes to a screw on connector at the back of the Pace STB for the TV, the other goes to an identical screw connector on the back the device that states 'CABLE MODEM' and 'AOL-HSM06' on the front.
The rear has two other connectors - one USB (unused), and one RJ45 ethernet connector.
The RJ45 connects via Cat5 cable to the ethernet card in the PC (Windows XP Home)
The connection to the internet is via AOL9 and it quite clearly states 'Initialising DSL modem' and quickly goes through the 4 steps of logging on to open up AOL's default interface. I can't say whether the messages from the AOL dialup routine are indicative of what's actually happening. I just read what it says - it may be doing something else entirely on connection.
Putting the router between the PC and the modem stops AOL connecting with the error code AC-3100 and five possible resolution messages (ie. your firewall is blocking everything, the modem isn't on, you've forgotten your screen name).
I have tried everything I know the make the router invisible to AOL, but failed.
The phrase 'The line going to the cable modem is in lieu of a connection to a standard telephone line' means the white coax cable screwed in the back of the cable modem instead of an RJ11 to BT plug type cable that a standard modem uses.

I have taken the router out of the equation so the PC connects directly to the modem, and it all works nicely again.
I have looked at the two links provided and it sound similar, but isn't quite the same.
If the connection from the modem was a straightforward RJ11 and microfilter job the a BT master socket, I would have been finished in seconds. My nephew had this sort of connection at my sister's house and setting up wireless was a doddle there. I foolishly assumed that this other set up would be as easy.
Does this have anything to do with the matter 'Data Over Cable Service Interface Specifications (DOCSIS)'?
I will have to wait a few days to get IP addresses as he's on the road for a few days.
Still utterly confused.
Rick

[updater]

As a full stop on this, I have found out via AOL that wireless and the current setup don't mix. They are doing trials in the US with something similar to the NETGEAR CG814GCMR, but not here and not now.

For those who wanted photographs of the setup I was attempting to make wireless, see below.