Error messages on website after wordpress update

Hello,

Today I have updated my wordpress site to 4.2.2 and along with that other plugins were also updated. However after the update I start getting below message on top of my website:

Warning: call_user_func_array() expects parameter 1 to be a valid callback, function ‘activity_publish_custom_post_types’ not found or invalid function name in /home/content/p3pnexwpnas07_data03/56/2642656/html/wp-includes/plugin.php on line 213

Warning: Invalid argument supplied for foreach() in /home/content/p3pnexwpnas07_data03/56/2642656/html/wp-content/plugins/buddypress/bp-blogs/bp-blogs-loader.php on line 97

I am not a developer and not sure how to access these files. Can anyone help me with the steps to resolve this issue.

Thanks in advance.

Regards,
Manjyot