I actually asked one of the developers about this a few months back.
He told me that AHP goes out and checks for a certain file on X10's servers, to determine if there is an update or not.
Apparently, that file isn't getting updated properly (or the format of it changed, or something).
It is on their list to fix it (or so they say), but there is no way to know when (or if) it will ever get fixed.
EDIT: It looks like it makes a call to "
http://software.x10.com/cgi-bin/checkfornewrelease.cgi", with a HEX value after the question mark. I'm guessing that hex value has something to do with the current version number.
However, that file doesn't exist, and you get dumped to the homepage.
I'm willing to bet that's a big part of the problem with the "check for updates" function not working.