Since the System Restore Points feature was broken in the previous two releases, trying to upgrade from Akeeba Backup Professional 3.3.11 or 3.3.12 to 3.3.13 will fail. If this happens on your site, please go to your site's backend, click on Extensions, Plugin Manager, locate the "System - System Restore Points" plugin and disable it.
i had it this problem but i did what you said but my question is are we suppose to enable after we install it or leave it disable ?
narkuz