After publishing the latest version of my survey (which is quite long, xls attached) I get the above error message when I try to open the survey in the web form. No error message during publishing. On Samsung Tablet it takes long (not to say forever...) to open but it opens eventually, iPhone is much quicker.
Published with Connect 3.1.126
Edit: I already tried to recreate the survey by publishing it under a different name and a new service but it didn't help.
I also had the brilliant idea to check the choice names and found a couple of apostrophs and blanks that I removed and deleted and published the survey again but no change.