Hi Geet,
I have heard of this happening from time to time with downloading PDF files. It may be that the browser is not reassembling the packets in the right order.
The normal suggestions are
try to do a download then, leaving your browser window open, test the download. If it failed, try it again.
(Supposedly the second attempt to download from the same site without having closed the window or navigated elsewhere, sometimes works).try a different browsertry a different ISP By the way - for download, read "choose to save the file directly to disk - don't try to view it inside your browser".
Good luck.
Regards, Andrew