cannot log in after new role was assigned to the user

hello

new user registered to our drupal site without any problems - he can log in, change his paswword, log out and log in again with the new password. when i assigned him to a new role, that consists only of the rules:

create story content
edit own story content
create url aliases

he is not able to log in. when he request for the new password and receives the link, again - he change the paswword to the new one, log out, tryes to log in with the new one, but not successful. then, when i remove him from the role, the problem continues the same way.

don't know, what is the problem. i have ldap module running. could this be the source of the problem?

thanks for any advice.

mirek