The help menu in Eclipse has no "Install new software" button so I can't install any new plugins:
I'm on Ubuntu 14.04. Here's my Eclipse version:
Eclipse Platform
Version: 4.3.2.v20140221-1852
Build id: M20140221-1700
I do not have a solution, but I figured out this workaround.
This opens up the dialog for installing. For me this happened today after installing a bunch of plugins from oracle and jboss
Best of luck
Run as Administrator.
Either Shift-Enter the program or right-click. The problem should be solved immediately.