Site Doesn't Load in Browser: Shows Server is Up

Hi, When I try to reach my site, I get the following errors:

Warning: require_once(assets/shared-ui/plugin-ui.php): failed to open stream: No such file or directory in /home/ghostlyactivities/ghostlyactivities.com/wp-content/plugins/snapshot/snapshot.php on line 52

Fatal error: require_once(): Failed opening required 'assets/shared-ui/plugin-ui.php' (include_path='.usr/local/lib/phpusr/local/php5/lib/pear') in /home/ghostlyactivities/ghostlyactivities.com/wp-content/plugins/snapshot/snapshot.php on line 52

It happened after I updated a plugin yesterday. I tried to restart my host, but that didn't work. I can't access my site to deactivate the snapshot plugin.

Thanks!