Problem in top categories in menu

Hi, i have a problem in my main menu.
My menu starts with home that links to http://www.electronix.gr/index.php?route=common/home
Then follows some top categories.
The first 4 top categories on mouse over point to http://www.electronix.gr/index.php?route=common/home even though in view source i see the right links and the submenus. The fifth and next top category works ok.
Any ideas?
The site with the menu in question is : http://www.electronix.gr/
The menu is not in english, but the first item in menu means home, the last is contact and all the others are top categories
Thank you in advance.

Because the header is too tall so it overlaps on the menu. You should cut transparent area in the logo.