Did you go to the actual calendar (not the feed)? There you can click on the file icon which brings up the window where you can get the iCal subscription.

Hmm...it works in iCal but Google Calendar rejects it. On the other hand this trick got us the GUFS calendar.

Update -- looks like the problem is just with the Haldane district calendar. I was able to import the ES, MS, and HS calendars.