I am having this same problem, except that no user is properly redirected. I have tried every suggestion offered at http://codex.wordpress.org/Login_Trouble except that following "Secure HTTPS ?" - all without success.
I have a church web site at http://www.stpetersparish.org on which I use WordPress for certain portions. It has been my plan to eventually use WP 1.5 for the entire site. To that end I have installed MySQL and WP 1.5 on my computer, imported the database from my web site, and changed the siteurl in the options table to http://stpeters/wp/.
Everything seems to be working, with WP using the Kubrick default theme. However, I cannot access the admin section to change to my custom theme. The log-in fails to redirect me to it.
My static non-WP pages are at http://stpeters/ and the WP files are at http://stpeters/wp/. Of course there are subdirectories such as stpeters/wp/wp-admin. I am working under Windows 2000, Apache2, PHP 3.0 and MySQL 4.1.
I can go to my home page at http://stpeters/index.html and from there I can successfully see the various categories using the pull down menu (Letters from the Rector, Vestry Minutes, etc), all in the default Kubrick Theme. But when I am at any of them (such as http://stpeters/wp/index.php?cat=5 Archive for the 'Letters from our Rector' Category) the right hand column does not include anything but the search textbox, the archive list, and the category list. This may be a feature of the Kubrick Theme. To see the log-in link I must delete the ?cat=5 in the address textbox and press enter. I then get the default index.php which shows all posts in all categories since Sept 2004. On the right in addition to the search box, archive list and category list are the WordPress link and a list of five items under "Meta" including the log-in link.
If I click on the log-in link I get the log-in page. Whether I log in as "admin" or any user, I do not get taken to the post page in admin. I stay at the login page and the URL in the address bar changes from
If I then use the back button to return to the index.php page, then refresh, the log-in link has changed to a log-out link. I presume this means that log-in set a cookie. I can undo this by going back to the login page and clicking on LogIn without entering a user name or password. No error is generated.
I am at a loss as to what else to try. Can anyone get me through this?