We’ve had a user who experienced similar issues with Outlook 2007 and he put together the following instructions that you might want to try.
2) Click New and then, in the space after “Enter the location of the Internet Calendar you want to add to Outlook:”, write or paste: [URL of ical file, which I shortened using tinyurl.com] and click Add. In response to the next prompt, change the Folder Name to something like Soccer if you’d like, then click OK. Click Close.
3) You should see a list of calendars to the left of your calendar. If you see the phrases My Calendars and Other Calendars, click on each until you see the list of calendars below them. If you don’t see a list of calendars, in the View menu, select Navigation Pane and make sure Normal is checked.
4) In the list of calendars, find the calendar name that you chose. Check the checkbox next to it. If it appears under Other Calendars, drag it to the My Calendars section.
5) You can view the sport calendar separately from your regular calendar or overlaid on it. To switch between these modes, find the tabs that appear above the calendars. Click the little arrows in those tabs to combine and separate the calendars.