The Downld function icons are grey because you're not downlding anything (I suspect.)

Go to your LW preferences (under the Limewire name at top-left on menu bar) & go to Downloads & make sure the no. of maximum downlds is set to at least one or more. And under Saving section, make days to keep incomplete files to 999 or something.

In fact, it might even be better to delete the LW preferences. It's often a good idea to delete your prefs if you change over to Pro. So whilst LW is closed (LW must be closed), delete the LW preferences found here: /Users/your_username/Library/Preferences/LimeWire

This will mean however that next time you open LW, you'll need to set all your options again so it might be wise to make a note of them before you do this. Post back if you still have problems.