Try visiting your website with /user/forgotpassword at the end. You may be able to reset the password after you receive the email the system generates.
i tried and it did not work.
when i have a look on the file log , i have this error message : <[Thu Oct 01 18:16:57 2009] [error] [client 193.252.7.123] PHP Warning: Unknown: POST Content-Length of 86 bytes exceeds the limit of 0 bytes in Unknown on line 0, referer: http://mfe.preprodmfe.org/ezpublish/index.php>
The last comment almost makes it look like you have limited post_max_size to 0 in php.ini. Other then that, you might need to truncate the ezsession table, experienced that this happens if it gets full (on debian based linux distro's where session gc setting is broken).
Besides the php/apache error log, the eZP one is also generally very useful; it is in the var/log dir of eZ Publish.
As a side test, you can try logging in to the front-end instead of the backend by just pointing the browser at http://site/index.php/user/login. Does it work?
Principal Consultant International Business
Member of the Community Project Board
If anyone else comes across this, this might help as well: http://ez.no/developer/forum/general/login_fails_in_infinit_change_password_dialog_loop_o_o#msg193315
