Setting Up A DLAN Wireless Extender Connection?

find the IP address of the dLAN Wireless Extender so I can go into advanced settings to set up the name, password etc. The Extender config tool provided cannot find it.I replaced my cheap WiFi extender which used to drop the connection all the time with a Devolo dLAN 200 AV Wireless-N Starter Kit, which was highly praised all over the place.How I set it up. The manual clearly states both the single Etherner port plug and the 3-ethernet plug should be slotted directly into the mains sockets which I have done. The smaller, single ethernet plug connects to my Router with the ethernet cable provided. The bigger plug is plugged into a different socket without any other cables attached. The power, house(dLAN), ethernet lights are green on both as well as the Wifi light is green on the extender.I used the dLAN cockpit program to add the Extender by entering the security code on the back, now both of them show up in the Cockpit interface and say "ON". I have the option to change the password for the entire network via the Cockpit, which I did. I assumed that's all the plug & play I had to do to make it work. Wrong. I cannot connect wirelessly at all. The network shows in the available list as devolo-000.......... with full signal, I click it, enter the password, it says authenticating and then drops.

The whole purpose for this is to have an extended Wifi Network around the house where the router cannot reach. But I cannot connect. Now i was reading on Davolo site where it says " You can set up or change the configuration of the dLAN® 200 AV Wireless N via the web interface. To access this interface, simply enter the known IP address of the product into any web browser (e.g.Internet Explorer) or call up the web interface via the dLAN® Cockpit."I also checked that apparently, the newer version, the dLAN 500 has a "config" button in the Cockpit application which takes you directly to the web interface to set up your wifi, but the 200 does not. I do not know what the IP address of the Extender is, I do not know how to reach the interface via my browser. I did have a feeling it had to be done because firstly I wanted to change the name of the Wifi network but couldn't figure out where.

I would also like to add that a program included in the set-up disc, called dLAN Wireless Extender Configuration doesn't seem to find it, so I cannot enter to look at any settings. It pops up with "the dLAN wireless extender was not found. is the dLan wireless extender switched on and properly connected to this computer's local network?"