Network Error when viewing contact from Joomla front end
It appears that something is misconfigured in your site.  From the frontend, you should only be able to go to "front-facing" pages, such as contribution pages, event forms, and profile forms (and I mean CiviCRM profiles, not the contact records themselves with the tabs and all).  Most importantly, contact search should not be available unless you have a profile with searchable fields configured, and you would most likely want to restrict those results to a group.