In addition to the previous poster please consider the following. If you download from a host that has three stars or less. It is likely to be a firewalled host so it has to establish a connection to your machine and essentially send you the file ie (push) it to you.
Now, the push request travels backup the network path to the machine that requested it. If a machine should leave the network along that chain of machines you will get a requery.
For example:
GetFile ===> A ==> B ==> C ==> Firewalled_Host_Files_I_Want
Requery <== A ==(?) <== C == Firewalled_Host_Files_I_Wanted
The connection never makes it back to me so I have to search for it again.
Hope this helps
http://www.leeware.com (FSP)