Installation has crashed my entire WP Dashboard, now what do I do?

I installed the WPMU dashboard so that I could install the Classifieds plugin. Now I get an error when I click on anything in my entire Wordpress dashboard. Fatal error: Allowed memory size of 41943040 bytes exhausted (tried to allocate 19456 bytes) in /home/vinta14/public_html/demo/wp-admin/includes/update.php on line 282. What do I do now?