Need help to connect iPhone 3G to D-Link D-2460T Wi-Fi Router

Hello,
    I'm trying to connect my iPhone 3G over Wi-Fi to a D-Link D-2460T router at my home.

The router is setup to offer DHCP and I have 1 desktop and 2 laptops connecting to it. All of them are able to fetch IP+DNS settings from the router. DHCP is configured to dish out IP's in the 10.19.168.x range. The security mode is WEP with a hex key.

The iPhone can detect the network without a hitch and asks me for the WEP key (password) when I try to join. Entering it makes it join the network... but for some reason it's unable to get a IP belonging to the pre-defined range in DHCP. The IP it gets belongs to a completely different segment, i.e. 169.254.186.x. Even the subnet mask isn't the standard 255.255.255.0.. instead it gets 255.255.0.0.

I tried setting a static IP, gateway and DNS settings... but that doesn't help either.

I've even tried dishing out fixed IP's based on the MAC of the iPhone... no avail !!!!

However, when I use the iPhone at my office - it connects fine to the office networks.. there are both secured and unsecured networks there.. and the iPhone connects to both without a hitch...

Has anyone faced a similar situation and managed to figure out a solution?

Thanks,
Sourjya