jos-Error: Application Instantiation Error

JFactory :: getApplication() @ /var/www/fisica/portal/index.php:27
JApplication :: getInstance() @ /var/www/fisica/portal/libraries/joomla/factory.php:102
JSite -> __construct() @ /var/www/fisica/portal/libraries/joomla/application/application.php:180
JApplication -> __construct() @ /var/www/fisica/portal/includes/application.php:47
JApplication -> _createSession() @ /var/www/fisica/portal/libraries/joomla/application/application.php:145
JFactory :: getSession() @ /var/www/fisica/portal/libraries/joomla/application/application.php:1020
JFactory :: createSession() @ /var/www/fisica/portal/libraries/joomla/factory.php:152
JSession :: getInstance() @ /var/www/fisica/portal/libraries/joomla/factory.php:656
JSession -> __construct() @ /var/www/fisica/portal/libraries/joomla/session/session.php:151
JSessionStorage :: getInstance() @ /var/www/fisica/portal/libraries/joomla/session/session.php:106
JSessionStorageMemcache -> __construct() @ /var/www/fisica/portal/libraries/joomla/session/storage.php:74
JError :: raiseError() @ /var/www/fisica/portal/libraries/joomla/session/storage/memcache.php:59
JError :: raise() @ /var/www/fisica/portal/libraries/joomla/error/error.php:251
JError :: throwError() @ /var/www/fisica/portal/libraries/joomla/error/error.php:176
JError :: handleCallback() @ /var/www/fisica/portal/libraries/joomla/error/error.php:214
JError :: customErrorPage() @ /var/www/fisica/portal/libraries/joomla/error/error.php:765
JFactory :: getApplication() @ /var/www/fisica/portal/libraries/joomla/error/error.php:784
JError :: raiseError() @ /var/www/fisica/portal/libraries/joomla/factory.php:99
JError :: raise() @ /var/www/fisica/portal/libraries/joomla/error/error.php:251