Dropdown Menus not working in IE 9

I’ve just purchased a theme from themeforest.net and the author is not giving support as he should be. So, I’m trying to find support elsewhere. The first level of the dropdown works fine, but the 2nd…3rd etc. are not appearing in Internet Explorer 9…and probably not in older versions, but I only have IE9 to test it with.

Link to my site in progress: https://www.design.hayleytarrant.com/mobilization

Here’s some code:

[chunks of code must be placed at pastebin.com]

Any help would be GREATLY appreciated!
Thanks,
Hayley