No reason the engine should be in the DAT updates anyway--it's called DAT, not engine+DAT.
I wish I could help you, but have no idea why that site is hiding from you. Only thought would be an infection perhaps.
They often block security sites.
I'm going offline for the night, so good luck.
Gah, turns out I had a proxy for the ftp protocol in my web browser (Firefox) which was screwing things up. I removed it ("localhost") and can connect to the ftp site fine now.
LOL...a big oops.
Just moving this thread to the Business General Discussion area.