Many thanks for the photos, helped a lot.
Looking at the photos, not sure that is not just dirty, but if your convinced it is burnt it needs replacing. See here
Looking at the wiring you have two extensions, is that correct?
The white/blue wire for one of the extensions (on the faceplate) does not look to be fully into the IDC connector, I would gently push it home.
Also check that the only wires connected in the extensions are the blue/white and the white/blue in terminal 2 & 5. If the ring wire (terminal 3) is connected in the extensions it will still feed interference into the system and hence to the router.
Hope that helps
Edited by Hatari (Sun 31-Jul-11 17:44:12)