I am not sure I understand this, too early in the morning, but let´s give it a try.
You say you have 1.4 GB left on the disc space, is that your server space or your local computers disc space? I am seeing a possiblity here that your local computer space are saying something like "this file is too big for me to download)".
As for the corruption, please see if this post helps. If that posts information don´t help, I would reopen the ticket and ask the techs what to do.