When using LDAP on-the-fly user creation, if username and password provided are correct but any required field (First Name, Last Name, E-mail) could not be fetched from server, Redmine returns a unhelpful error message:

"Invalid user or password"

A better informative message could be:

"Redmine could not retrieve enough information from LDAP server to enable your account. Please, contact your network administrator."

I lost one hour because some accounts were without e-mail address on my LDAP server. :)

Please also add a warning about this into Wiki (http://www.redmine.org/wiki/redmine/RedmineLDAP).
I tried, but it is read-only.