Critical Error

Please help me repair and PREVENT future such events.

Twice in two months, after getting a message that WP has automatically updated my website, I get a Critical Error message. HostGator has investigated and determined that the problem has to do with PHP function.I am technologically challenged and do not understand–much less know how to fix! Here are the error messages from April:

“Notice: register_uninstall_hook was called incorrectly. Only a static class method or function can be used in an uninstall hook. Please see Debugging in WordPress for more information. (This message was added in version 3.1.0.) in /home3/nancykay/public_html/wp-includes/functions.php on line 5229

“Fatal error: Uncaught Error: Call to undefined function highend_main_wrapper_class() in /home3/nancykay/public_html/wp-content/themes/HighendWP/header.php:31 Stack trace: #0 /home3/nancykay/public_html/wp-includes/template.php(730): require_once() #1 /home3/nancykay/public_html/wp-includes/template.php(676): load_template(‘/home3/nancykay…’, true, Array) #2 /home3/nancykay/public_html/wp-includes/general-template.php(48): locate_template(Array, true, true, Array) #3 /home3/nancykay/public_html/wp-content/themes/HighendWP/page.php(18): get_header() #4 /home3/nancykay/public_html/wp-includes/template-loader.php(106): include(‘/home3/nancykay…’) #5 /home3/nancykay/public_html/wp-blog-header.php(19): require_once(‘/home3/nancykay…’) #6 /home3/nancykay/public_html/index.php(17): require(‘/home3/nancykay…’) #7 {main} thrown in /home3/nancykay/public_html/wp-content/themes/HighendWP/header.php on line 31”

Please advise via email to nkwessman@comcast.net. Thank you.