Problem With Hoe Wirelss Connection

We've Had This Wireless Modem Running In Our House For About A Year Now. It Was Awesome When We Got It But Now It Comes Up With:

Cofiguration Test Failed

It Doesnt Come Up All The Time Just SOmetimes...

Also It Used To Only Come Up When Someone Rang. We Got The Local Electricity Company To COme In And Install A New Phone Jack So There Wasn't A Cord Running From 1 Side To The Other. But It Still Does It.

Help Would Be Much Appreciated!