Hi Jamila,
Thank you again for the details, I was able to find the issue. It seems like there was a problem executing one or more shortcodes during the keyword extraction process. I wasn’t able to pinpoint which one exactly, but luckily there is an option on the plug-in back-end to disable shortcode execution.
For future reference, I’ve changed two of the options: http://i.imgur.com/6L3TVPt.png
The error should be gone now on all pages, hopefully.