Trying to replace text -- get a preg_replace() warning

Network activated this plugin and attempted to replace the "thank you... " text at the bottom of the admin screen. But I get a whole page full of this error:

Warning: preg_replace() [function.preg-replace]: Unknown modifier '/' in /home/playhous/public_html/wp-content/plugins/site-wide-text-change/site-wide-text-change.php on line 436

I left the text domain blank.

Any ideas?? Thanks!