Hi,

In Audiogalaxy, you would request a file through a website, and audiogalaxy would arrange to have it sent to you. This is not how Gnutella functions. If you request a file through LimeWire, you are requesting it directly from another computer. If that computer is unavailable for some reason, it may be impossible to complete the download. Since only about a quarter of files on the network are currently hashed, it can be difficult to find a replacement on a requery. If a download request fails, you'll probably need to select another download source, or perhaps even repeat the search.
In many ways this difference can be an advantage. If you don't like your download speed, you can try downloading from a faster computer since you have better control over file transfers.

Good luck!

Avi