Download a file from here & see what speed you get
http://www.magnetmix.com/video.shtml

Has this just started happening? Do you see the firewall icon (brick wall)? Have you used other p2p apps & if so, does the same thing happen? How many green comection bars do you see?
Do a speed test & tell us your speeds
http://www.dslreports.com/speedtest?more=1

What are your details?

OS(Win XP etc)
LW & Java version (help > about LW & you'll see)
Firewall you're using
Modem/router brand & model
ISP
Connection type (DSL etc)
Where you connect from (home, school etc)
Are you sharing a connection with other computers
Is this your first try with LW