[TWD-Tony]

Yes it's working fine from here, maybe you are getting blocked by the server firewall - I know this happens from time to time with my clients... If they try and access soemthing like email to many times per hour the firewall kicks in and blocks them for a pre-determined period.

As for the wp_categories issue, if the new version of WP doesn't use that table then it looks like a previous update / upgrade didn't work properly? Some part of WP is still looking for that table.

Maybe you could try a fresh install in a sub folder and try copying the content accross at DB level - if that works out then you can copy your fresh install back accross to the live site...