Its been answered a lot many times in this forum and searching google for this will have given you the solution. ITs basically a server side problem, which restrict joomla in memory usage. Currently your server setup restrict memory usage to 32 MB.
This can be solved either by use of php.ini overrides, in some cases .htaccess overrides.
FOr easy fix download and Install >> http://extensions.joomla.org/extensions/hosting-a-servers/servers/7747 and set it to 100 MB and it should work well.
If still confused, pass on your admin login / ftp login and i shall set it up for you.
Arvind
