Corrupted files
If you get a message when installing a file that the file is corrupt,
the most common reason is an incomplete download. This might happen if
there is network congestion and the download is aborted, or if some
other problem caused the connection to be reset before the download
completed. To recover, delete the old corrupted file and then download
again. Check that the final size of the file you downloaded matches the
size shown on the website.
If you are working through a proxy server, it is possible that there
could be a corrupt copy of the file you are attempting to download on
the proxy, resulting in the same corrupt download every time. To avoid
this, temporarily disable the proxy before you begin downloading. Proxy
servers are usually set up and maintained by your ISP, so contact them
if you need help with this.
Slow downloads
If you find that the download is taking a long time, try again a
little later or early in the morning. Internet connectivity is shared by
thousands of other users, so if you try to download during periods of
peak activity, the download is likely to be slow regardless of the speed
of your modem.
Slow downloads can also lead to corrupt files because the browser
might eventually give up if the download seems to be taking too long.
Very often it won't even warn you after giving up, and will leave a
corrupted file where the full download was supposed to have been.
If you are frequently plagued with slow or corrupted downloads, you
might need to contact your ISP for assistance.