It does look that way doesn't it! I'd suggest you contact the isp & find out whether they have applied a filter or port block or other blocking method on your use of LW.
As simple test for port block of 6346 is to use your browser & visit this page:
http://www3.limewire.com:6346/ The page should say ‘Test Page was a Success’. What happens when you go there?
I remember reading another member's comment about their isp on the forum before that if you share/upload more than a certain amount of files then it's seen as a server.
I came across this comment, quote: "I also believe they are hindering P2P uploads on residential accounts because they consider any running and connected P2P application a server no matter what is being shared, legal and illegal."
http://www.dslreports.com/forum/rema...xhsi;mode=nest