Connection difficulties with 2x Powerline AV 200 adapters

I've researched this problem [Local Area Connection doesn't have a valid IP configuration] and have yet to find a solution. I've tried all the suggestions i've found, none work. I have four powerline adapters but can not get more than two to work at the same time. The addition of the third and/or fourth just wont work. I have three desktops I want on the powerlines but am stuck with the third desktop on wifi. I went with the pwrlines because I was too lazy to string cat5 in my new home and wifi just wasn't reaching the farther reaches of my home. I know it's not my house wiring because i can get may laptop to join the network from any outlet in the house as long as only one PC is on the network. As soon as i attempt to add the third i'm out of luck. I keep reading that you're supposed to be able to add just about as many as you want (don't know if there is a limit) but for me I have two additional units I can't use. Considering all the time and effort I have spent trying to fix this problem I could have strung the cat5 twice over. Anyone out there having similar multi adapter problems?