I posted a possible solution to the signing-on problem on Nigel's site a few weeks back, so here is what I offered. It worked for me and seems to have worked for others who tried it and replied on the forum.

"Nigel, I have just gone to my browser - Mozilla Firefox - and gone to the Options/privacy/Custom Settings and deleted the cookies which were there under your site - http://www.nigelgatherer.com. When I went back on to the forum I could log in and am now sending this message! Hope this might help you and other members."