problem with $.mobile.selectmenu.prototype.options.nativeMenu

problem with $.mobile.selectmenu.prototype.options.nativeMenu

I have been using $.mobile.selectmenu.prototype.options.nativeMenu = false; in my app, but now I want to change to using the native dropdowns. However, if I remove this line from my code (or change it to true) then the page will not load. I get an error 

  1. Uncaught TypeError: Object has no method 'addClass' jquery.mobile-1.2.0.min.js:2
    1. (anonymous function) jquery.mobile-1.2.0.min.js:2
    2. (anonymous function) jquery-1.7.1.min.js:4
    3. e.extend.each jquery-1.7.1.min.js:2
    4. e.fn.e.each jquery-1.7.1.min.js:2
    5. f.fn.extend.html jquery-1.7.1.min.js:4
    6. a.widget.setButtonText jquery.mobile-1.2.0.min.js:2
    7. (anonymous function) jquery.mobile-1.2.0.min.js:2
    8. a.widget._create jquery.mobile-1.2.0.min.js:2
    9. (anonymous function) jquery.mobile-1.2.0.min.js:2
    10. a.Widget._createWidget jquery.mobile-1.2.0.min.js:2
    11. a.widget._createWidget jquery.mobile-1.2.0.min.js:2
    12. (anonymous function) jquery.mobile-1.2.0.min.js:2
    13. a.(anonymous function).(anonymous function) jquery.mobile-1.2.0.min.js:2
    14. (anonymous function) jquery.mobile-1.2.0.min.js:2
    15. e.extend.each jquery-1.7.1.min.js:2
    16. e.fn.e.each jquery-1.7.1.min.js:2
    17. a.fn.(anonymous function) jquery.mobile-1.2.0.min.js:2
    18. a.widget.enhance jquery.mobile-1.2.0.min.js:2
    19. (anonymous function) jquery.mobile-1.2.0.min.js:2
    20. a.widget.enhanceWithin jquery.mobile-1.2.0.min.js:2
    21. (anonymous function) jquery.mobile-1.2.0.min.js:2
    22. (anonymous function) jquery.mobile-1.2.0.min.js:2
    23. f.event.dispatch jquery-1.7.1.min.js:3
    25. f.event.trigger jquery-1.7.1.min.js:3
    26. (anonymous function) jquery-1.7.1.min.js:3
    27. e.extend.each jquery-1.7.1.min.js:2
    28. e.fn.e.each jquery-1.7.1.min.js:2
    29. f.fn.extend.trigger jquery-1.7.1.min.js:3
    30. a.Widget._trigger jquery.mobile-1.2.0.min.js:2
    31. a.Widget._createWidget jquery.mobile-1.2.0.min.js:2
    32. a.widget._createWidget jquery.mobile-1.2.0.min.js:2
    33. (anonymous function) jquery.mobile-1.2.0.min.js:2
    34. a.(anonymous function).(anonymous function) jquery.mobile-1.2.0.min.js:2
    35. (anonymous function) jquery.mobile-1.2.0.min.js:2
    36. e.extend.each jquery-1.7.1.min.js:2
    37. e.fn.e.each jquery-1.7.1.min.js:2
    38. a.fn.(anonymous function) jquery.mobile-1.2.0.min.js:2
    40. a.mobile.changePage jquery.mobile-1.2.0.min.js:2
    41. a.extend.initializePage jquery.mobile-1.2.0.min.js:2
    42. (anonymous function) jquery.mobile-1.2.0.min.js:2
    45. e.extend.ready jquery-1.7.1.min.js:2
    46. c.addEventListener.B jquery-1.7.1.min.js:2

I have two pages setup for you to look at, they are exactly the same except that one has this line and one does not. Any help is appreciated.