Plugs Upgrade craches site

I jusr tried to auto upgrade two plug ins, one of which was askimet. It showed that the upgrade had failed and then no plugs where shown, and shortly after the site crashed showing these error:
Warning: require(/home/xxxx/public_html/cm/wp-includes/compat.php) [function.require]: failed to open stream: Permission denied in /home/xxxx/public_html/cm/wp-settings.php on line 207

Fatal error: require() [function.require]: Failed opening required ‘/home/xxxx/public_html/cm/wp-includes/compat.php’ (include_path=’.:/usr/lib/php:/usr/local/lib/php’) in /home/xxxx/public_html/cm/wp-settings.php on line 207

I have very little understanding of this, so any plain english help would be much appreciated :))