Just installed, nothing works?

[NedFlanders]

I just installed Mysidia onto my site, now my site is completely broken. If I try to go to the adminCP link, it says;

Not Found
The requested URL /admincp/index was not found on this server.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

If I try to log in, it says

Fatal error: Class 'AppController' not found in /home/furrysit/public_html/Mysidia Adoptables v1.3.4/login.php on line 3

and If I try to go to the website itself, it says

Warning: require(/usr/local/apache/htdocs/inc/smarty/Smarty.class.php): failed to open stream: No such file or directory in /home/furrysit/public_html/Mysidia Adoptables v1.3.4/classes/class_mysidia.php on line 326

Warning: require(/usr/local/apache/htdocs/inc/smarty/Smarty.class.php): failed to open stream: No such file or directory in /home/furrysit/public_html/Mysidia Adoptables v1.3.4/classes/class_mysidia.php on line 326

Fatal error: require(): Failed opening required '/usr/local/apache/htdocs/inc/smarty/Smarty.class.php' (include_path='.:/opt/alt/php55/usr/share/pear:/opt/alt/php55/usr/share/php') in /home/furrysit/public_html/Mysidia Adoptables v1.3.4/classes/class_mysidia.php on line 326

I don't know what to do!