Sorry about this but - for various technical reasons too tedious to explain - the users list on this site has been inundated with visibly fraudulent users (going by the various character patterns used which look all too much like computer-generated user id's). It seems that their actual attempts to post to the site have been blocked, but nonetheless we're going to go ahead and block what seem to be the offending user IDs.
Now it's always possible that we may block a bona fide id by mistake. If you try to logon and discover that your ID is blocked, use the contact form to send us a message and we'll reinstate you.
If we don't hear anything from the blocked user IDs, then in a few weeks time they will be deleted (again, if you got deleted by mistake then you can always just ask for a new user ID).
Sorry about this, but spam attacks are virtually a permanent feature of the net, we're doing our best to keep them off but occasional problems are more or less inevitable.