Memory errors

My site is producing errors when I try and go into edit pages.

Error Message is:
Fatal error: Allowed memory size of 41943040 bytes exhausted (tried to allocate 1798144 bytes) in /home/sites/b-tac.co.uk/public_html/wp-content/plugins/shortcodes-ultimate/includes/class-shortcodes-ultimate.php on line 168 Fatal error: Allowed memory size of 41943040 bytes exhausted (tried to allocate 1798144 bytes) in /home/sites/b-tac.co.uk/public_html/wp-includes/pomo/plural-forms.php on line 83