I guess you mean this one (which doesn't seem to have been updated since 2000 and probably doesn't support the aligned lyrics, w:, too well) . If so what you are trying to download is zip file. I've just downloaded it so there is no problem with the site. If you are at a university, I'd suggest asking someone who knows that system as it could be something there blocking the download.

If you like Noteworthy, you may like to take a look at ABC2NWC. This is a shareware program that converts abc to noteworthy and Noteworthy to abc.

You might also like to take a look at Melody Assistant. This is a bit like Noteworthy but it can handle abc without the need to run other conversions.

Jon