You have debugged this pretty far. There are objects that salesforce will not let Skuid interact with.  Generally these objects don’t allow any queries,  but in this case it looks like they allow organization data to be read, but no updated. 

You could create that nice organization detail page in skuid that shows things elegantly,  but then put an edit button that goes to the standard Edit org page (/{{{Id}}}/e)

Sorry about this. 

Thanks for the info. That’s a good semi-work around that I’ll try.

This is odd.  The Org data should be something the user can update. This article says that the object supports the update() call. 
https://www.salesforce.com/developer/docs/api/Content/sforce_api_objects_organization.htm

Are we missing something? Is there a list of objects that are not updateable?

Has anyone else been able to successfully update the organization object through Skuid? Would really like to allow customers to update their own address and info in our Skuid page rather than having to redirect out of our package.