Hello mate!
How did you install the site?
Have you used the quickstart zip file? and upload this file to your host
or did you upload file by file ?
When i accessed the plugin manager , i saw that:
Joomla!
500 – An error has occurred.
Layout default not found
=> administrator/component/com_plugins folder is having same problems, may be files were in-corrupted
Now:
1) you get the com_plugins folder to upgrade for your folder
2) you upload the quickstart zip file to your host, and then up zip => re-configure the database information, something else in the configuration.php, this will replace current project folder.