1. Tip: Purge the Downloads Queue!
2. After opening LW wait 10 to 20 mins before using. Let it settle down 1st.
3. Don't use the Resume button on all incomplete files. This has side-fx & can affect LW's connection quality. This will also stress LW & your comp. If you use Resume/Find sources then just apply it to a couple or so at one time.
4. Go to Tools>Options>Connections & untick connect on startup & press apply. Then go to menu File>Disconnect, wait a minute or so & then go File>Connect & wait many mins to give it a chance to connect.
5. Make sure your firewalls are properly configured to allow LW full access: http://www.limewire.com/english/content/firewalls.shtml

Also did you try uninstalling Java 1.4.2 & upgrading to Java 1.5 It works for some but not others. See 1st link above for java. Install it from your computer not over the net.