Warning Messages reported on WordPress Dashboard

Hello-

So I have about 150 warning messages showing up on my Dasboard. All of them are some form of this:
Warning: simplexml_load_string() [function.simplexml-load-string]: Entity: line 9: parser error : Opening and ending tag mismatch: body line 4 and html in /home/content/l/e/t/letutors/html/wp-content/themes/percivale/functions/theme-updates/notify.php on line 139

I went into the wp-config file and confirmed the the WP-Debug value is set to false. I also updated my version of PHP to 5.3 on my hosting provider.

I went into the functions file and added the following code:

@ini_set('display_errors',0);

This resolved the warnings or hid them but what it also did was hide the login screen to the website so https://www.mywebsite.com/wp-admin returned a blank page with nothing on it. So that wont work.

I updated all the plugins and then deactivated and reactivated them one at a time but the warning messages still showed each time.

Any help would be greatly appreciated. Thanks

Matt