[TYPO3-calendar] Calendar Base Error

[Ron Strik]

Hi Group,

I'm not so experienced in the use of the Calendar extension, but had 
(until now) a working calendar in my website.
Now I have updated my calendar from v1.4.0 to v1.4.2 because i missed 
the first week of January in my month view.
But after the update I got a Calendar Base Error... 
http://www.atletiekstad.nl/start/ and no template file found on the 
month view http://www.atletiekstad.nl/nc/atletiekagenda/.

Anyone with good tips for me? I use Typo3 v4.4.7. Thanks for your help 
in advance.

-- 
Vriendelijke groeten / Kind regards

Ron Strik