ALERT - Include filename
“mod_mainmenu/../../../../modules/mod_mainmenu/tmpl/default.php') contains too many “../”

The error above means that you have exceeded the limit (usually 4) of  “../” to the included files.
Most likely you're using a template on Artisteer CMS Joomla, in fact, the bug has been fixed with later versions of Artisteer, but can be solved manually by replacing the following line of code:
require_once dirname(__FILE__) .
str_replace('/', DIRECTORY_SEPARATOR, '/../../../../modules/mod_mainmenu/tmpl/default.php');

present in the file TemplateName\html\mod_mainmenu\default.php with this line:
require_once realpath(dirname(__FILE__) .
str_replace('/', DIRECTORY_SEPARATOR, '/../../../../modules/mod_mainmenu/tmpl/default.php'));