lol Try deleting your prefs & see if that helps. (If you delete your prefs you'll need to set them again, so make a note of your settings first.)

Most probably you'll find your preferences here: OS X: /Users/your_username/Library/Preferences/LimeWire else, search your computer (CMD+S) for limewire. The LW preference file is named .limewire

Also if it happens again, do another search for more sources. Search results go stale after a certain amount of time. Some days, LW needs just that bit of baby-sitting. If it stops, delete it from the dwnld list & re-select to dwnld from the search results. If it doesn't start dwnlding, do another search.