When I try to edit a Text Block in the site I get this error:

Unhandled Runtime Error TypeError: Cannot set properties of undefined (setting 'external_plugins')

Please open the browser console for more information!

Call Stack Object.extend (4:11547)

DO (4:378195)

(4:398569)

new OT (4:398589)

Object.execCommand (4:423694)

(2:545406)

tl (2:557669)

wu (2:577791)

(2:576533)

bu (2:576598)

Can you help?