Error saving changes with all Upfront themes

Whenever I try to save changes in any Upfront theme, I get this error.
there has been an error saving you changes

Here is a screenshot showing the error.
https://drive.google.com/file/d/0Bwy8OWRY4_Pkalh2Z3RJMF9iVTg/view

My web host is Site5, support access is enabled. Any suggestions?