plugin installation fatal error

while using wordpress’s own plugin browser/installer… i keep getting fatal errors:

Fatal error: Cannot redeclare pclziputilpathreduction() (previously declared in /home/krisinu/stumblingscholar.com/wp-content/plugins/wordpress-automatic-upgrade/lib/pclzip.lib.php:5421) in /home/krisinu/stumblingscholar.com/wp-admin/includes/class-pclzip.php on line 5498

Anyone know what could be wrong?