When I open up the special page, I get no option to add questions. I have seen this issue before but on my page, I have no custom JavaScript. I don't know if it matters, but when I downloaded the file from this webpage multiple times the directories were always missing various files, so I downloaded the entire set from the GitHub page.
Topic on Extension talk:Survey/Flow
We're checking this.
We have a patch going through internal review.
This should be resolved in the latest versions of master and REL1_39 branches. Let us know if you still have any issues.