Hi,
"Allowed memory size of 67108864 bytes exhausted"
it clearly says that it needs more memory to execute.
I recommend to increse php memory limit, that will solve this problem.
insert memory_limit = 16M to your php.ini file . This will increase your php memory limit to 16 MB. This is also the recommended method (, if you have access) . Don't forget to properly locate your php.ini file!
You can add ini_set('memory_limit', '16M'); add the top your codes (You can add this to your index.php file which is in the root your Joomla! installation. This is not the suggested way because of index.php patch)
Adding php_value memory_limit 16M to your .htaccess file in the Joomla! root (This will not work in windows servers)