[EventCalendar] Problem with iCalendar link - 'object not found'

[admin at challengebritain.co.uk]

Hi all ...

I'm sorry, I'm a complete CMS virgin and have no idea how to work  
around this (I guess I need to install an iCalendar - but which one?)  
...

First off - EC3 - superb - thank-you

I have encountered one problem, (that you also seem to have on your  
own site), that you can see here :
http://www.challengebritain.co.uk

At the head of the Calendar, between the start & end months, there is  
a small logo ... you hover over it and it says 'iCalendar' with a web  
link (in my case) to :
http://www.challengebritain.co.uk/?ec3_ical

When I click on it, I get a pop-up box that says "The operation  
failed. An object could not be found"

I'm stumped and hope you can help?

Regards,

Simon Hobson