Try disabling ultrapeer capabilities (tools > options > speed). Disable any iTunes sharing options that you have enabled. How many files are you downloading at once? Reduce your simultaneous downloads to just 1 or 2.
Also reduce your upload & download bandwidth a bit. To find out the best setting for both bandwidth sliders, do a speed test here & then follow the setup advice in the thread below
Configuring LW for best performance

Remove your current Java version & reinstall JRE using the offline installer here
http://java.sun.com/javase/downloads/index.jsp