There I am experiencing a very annoying issue with this

Hi There

I am experiencing a very annoying issue with this site (and other sites I have loaded themes onto). Whenever I try and save my changes to the theme, it gives me a notice saying the following: There has been an error saving your changes.

I am using the Fixer theme in this case, although I was experiencing the same issue with another site using the "Scribe" theme.

Please note also that I am not making any drastic changes here. Even just minor changes to the text or color in the header etc.

Please help.
Kyle