Nuntius Theme Dropdown menu problems

I am customizing the Nuntius theme to suit my web design and I just started adding my menu items. However, my submenu isn’t working properly. Every time I hover over the Tab to bring up the submenu from my primary menu it will display the submenu, but about 50px down from the main menu so there is a big gap, and as soon as I move the cursor to go to select an item the submenu disappears. I think the gap is making the browser think I have left the tab to select the submenu. Where do I go in the stylesheet to get rid of this gap?

All help will be appreciated