I received following error

Fatal error: Cannot redeclare password_hash() in /var/www/phpldapadmin/lib/functions.php on line 2225

after installation of phpldapadmin on ubuntu 12.04 with php 5.5. Later I found that latest version of phpldapadmin is not compatible with php 5.5, since there are some problems with function names conventions. Best solution is to downgrade your php version to 5.4 or even 5.3.

This bug is quite fresh, announced in May 2014 :  https://launchpad.net/ubuntu/+source/phpldapadmin/1.2.2-5ubuntu1.1