1.
I might have moved the page within the website.
2.
The link you followed may be incorrect or I might have permanently deleted the page.
3.
I'm updating and I'm not finished yet, try again later (might be a long wait).
4.
A required file doesn't exist because it was previously updated and has a new name.
5.
The link is just plain broken - yikes!
6.
Larry, your host, (that would be ME), goofed and something needs to be fixed.