Woody,
1) If you get the correct answer from the tab test in the builder, then the problem must be in something else
2) Please try to test your page, actions, etc. in same order in Appery.io tester with opened console (press F12 in Chrome)
3) This is an example of error in console
http://gyazo.com/403dbe12cfdfe483e82c... - on the left side cause of error, on the right line and file. We would like to see the file name and line.
Also if you try this in your console in browser, then you can expand your error to see full stack