If your Moodle 2.7 was installed via cPanel, how did you add the theme?
Did you use the Moodle setting Site Administration > Plugin > Install Add-on?
if so did it install correctly?
To remove (uninstall) a theme you need to go to
Administration > Site Administration > Plugin > Manage plugins
Then scroll to the bottom of the page to find the Dynamic theme and click the link to 'uninstall'
If you cannot get into your Moodle site then you will need to locate the theme in your File Manager
moodle / theme / dynamic
and delete it.
hope this helps?