Some general notes, maybe that helps.

Some files are just very rare. If you don't have a least 3 or so hosts serving the file, it's likely that a download won't complete.

If all the hosts from your initial search that have the file disconnect, the download stopps. You can in that case search again for the same file and if limewire finds new hosts that have the file, it will resume download.

lastly:

Do you use a router or a firewall? That can seriously limit your ability to donwload. If yes, read the related section in the FAQ, it will tell you how to circumvent that limitation by port forwarding and forcing your IP.

Good luck!