[Coco] Downloading problems

[Bill]

I went to
http://sourceforge.net/apps/mediawiki/nitros9/index.php?title%3DMain_Page
and clicked on the link for the "one (large) ZIP file", downloaded the
nitros9project.zip, but when I tried to open it, I got this message: "Cannot
open file: it does not appear to be a valid archive. If you downloaded this
file try downloading it again". So, I did, and I keep getting the same
error. The same with the link for the "individual disk images".

Help?

Thanks