Why can't I add a menu item in the main menu or see an item property? Is Unity the culprit ?
I am using Ubuntu 11.10.
Yup, it's Unity. Assuming you're talking about the top bar (also known as the Unity Global Menu), you might find one or the other of these questions helpful:
If you're talking about the launcher (also Unity) you can add items to it by choosing "keep in launcher" while they're open.