You are one of the few people that have actually done their homework before posting Good job

The only thing that I can think of that might cause a problem like that is some kind of conflict between firewalls or antivirus/antispyware programs or if you are sharing an extreme amount of files which (sometimes) can cause problems.

Is that the speed for many downloads or is it 2 KB total. If you have too many things downloading at once that could cause some problems as well

Are you a new user of Limewire ? or has it worked before

What Firewall are you using if any ? (never use more than one)

Also what Antivirus/antispywareprograms do you use ?

Do you use UPnP ? (in the advanced<firewall)

if you do. Are you sure that your router is configured correctly for it ?

What version Java ?