Power Line Box Timing Out Web Browsers?

I recently got this box to let me run the network in my house though the power lines and into my computer, but since I started using it, I'm getting random timeouts from all of my Web browsers. The boxes are plugged right into the wall, no extension cord or anything, but I still get the errors on every 3rd or 4th page I visit.

The weird thing is that everything else that required the Internet works fine. I left Eve running overnight to test it, and when I came back the next day, I was still online. I can't think of any reason for this to happen and Google is no help because nobody is really sure what these boxes are called!

The brand is Netgear and this is the only thing I've changed on the network since I started using the box.

Can anyone help?