If LW had been connecting & downlding fine but suddenly starts playing up then a simple deletion of LW's preferences whilst LW is closed can sometimes fix this (but make a note of all your settings 1st.) Another "simple" idea but it can work. LW preferences are found here: /Users/your_username/Library/Preferences/LimeWire

Another concept is your isp provider. There's lots of them out there who filter p2p programs b/c they use so much bandwidth.