Actually, limewire does support downloading from behind a firewall, but due to how firewalls work, if you are firewalled (that is if your limewire port cannot accept incoming connections), you cannot download directly from other firewalled users (from others who cannot accept connections). Web servers are accessible, even by firewalled users, because the web server does not have to make a connection to you, you make a connection to it, and the server admin has already punched a hole in their firewall (if they have one set up) to allow connections in for files and content to be served up.

Most Internet service providers rate their bandwidth in kilobits per second and the speeds that limewire displays are in kilobytes per second. There are 8 bits in a byte, so 8 kilobits is 1 kilobyte. That means that your connection's bandwidth, rated in kilobytes, is around 200 kilobytes per second downstream and 26 kilobytes per second upstream.

Transfer interrupted could mean various things as to why a transfer stopped, such as the user who is downloading from you cancelling the file transfer on their end, or they found another available source before they got an active slot in your queue, or are downloading from multiple sources at once and only needed a small part of the file from you (such as 50% of a file from 2 different sources), or it could be caused by limewire receiving no response from the remote downloader during an already in-progress transfer.