Too many errors on your plone site, i don't have the time to fix all.

First you customized "portlet_recent", and it was one of your problems.

Inside "portlet_recent", i replaced :

tal:define="last_login_time python:member.getProperty(DateTime());

by

tal:define="last_login_time python:member.getProperty(last_login_time, DateTime());

and added inside the catalog request

modified={'query': last_login_time, range : 'min'},

There is one other bug but it is better if you find a solution yourself. Go to http://biblioteconomia.objectis.net/manage_emergency to access ZMI