Warning messages in Origami theme

I am working on a wordpress site that is for another person. When she turned the site over to me, I changed the theme to Origami. I have written minimal CSS code, so far (all of which is working fine). But, any actions that I perform, be it creating a new page, saving, adding media…
I am getting a new screen with the message below. If I “arrow” back to what I needed to do, it tends to work the second time, but not always. Does anyone know what this means or how I can fix it?

Thanks!

Here is the message:

Warning: call_user_func_array() expects parameter 1 to be a valid callback, function ‘ola_mc_update_campaign_content’ not found or invalid function name in /home/sruslacker/public_html/wp-includes/plugin.php on line 496

Warning: Cannot modify header information – headers already sent by (output started at /home/sruslacker/public_html/wp-includes/plugin.php:496) in /home/sruslacker/public_html/wp-admin/post.php on line 233

Warning: Cannot modify header information – headers already sent by (output started at /home/sruslacker/public_html/wp-includes/plugin.php:496) in /home/sruslacker/public_html/wp-includes/pluggable.php on line 1178[/COLOR]