I notice that if you add a trailing "/" (ie,
http://www.safe4all.org/register/), then you get the proper registration page.
When I don't use the trailing "/", and attempt a telnet:
$ telnet www.safe4all.org 80
...
GET /register HTTP/1.1
HTTP/1.0 302 Found
...
Location: http://safe4all.org:8000/register/
So, it's redirecting to port 8000 of "safe4all.org". Check your SystemURL parameter from ACS Kernel. Or maybe your Tcl init file.
Hope these stabs in the dark help...