Nothing to do with the computer or program, I'd suggest it's slow upload speed from the uploader. They may be using dial up connection, else don't have much upload bandwidth & have several people alongside you uploading their files. Difficult to say. But let us know if this happens with any other downloads.

The download speed is nothing to do with the program as this thread topic refers to. Sometimes LW runs slowly on a computer with little ram or older slower internal computer technology which gives LW that laggy effect. Older Java was not super efficient either, especially Apple's java versions.