I built a WordPress for a client. Upgraded it to version 3.1.1 recently. I can login to the site from all my computers. My client can login from his work computer but not his home computer now. He has tried clearing cache, cookies, tried logging in on IE8, FF and Chrome. Neither username or password have changed. I tried adding a new user, he still cannot login to WP Admi, just keeps getting the Ooops message. Any ideas?