Buffalo Ethernet Converter (WLI-TX4-G54HP)

I recently purchased a Buffalo Ethernet Converter (WLI-TX4-G54HP), and have
had little success in getting it to connect to my existing home wireless
network, via a Netgear WPN824 router.
In order to maintain a connection, I need to place the Buffalo Ethernet
Converter within a few feet of the wireless router, however, this is
completely impractical as I was wanting to use it in another room, connected
to a Slingbox. I already have several bits of equipment around the house,
including a couple of laptops and a wireless IP camera. All these items
have been turned off as I have tried to configure the converter. The place
where I want to install the converter generally has a good to very good
reception, which I have confirmed using one of my laptops.

I have tried with several configerations, including changing the security
settings from WEP, WPA, WPA2 and then no security. In addition, I have
changed the channel numbers to avoid any potential conflict with any hidden
outlying networks. The SSID name is correct and have I set up the
configeration trying to use the converter on it's own MAC address and the
MAC address of the first item connected to it.

I have spent several hours trying to get the router to connect, but despite
numerous attempts, it fails. I would be grateful if anyone could offer any
insight into the problems I have been experiencing. My ultimate conclusion
would be that the unit is actually faulty, however, before returning the
product, I am wondering if there is anything anyone could suggest I try
before sending it back. The unit seems fine when configering it with the
router using the ethernet cable. It just won't connect wirelessly, which is
its prime purpose.