[TYPO3-ttnews] tt_news + cal: Division by zero

[Andreas Deininger]

Hallo,

I've installed the following extensions on my Typo3 instance, version 4.1.2:
News (tt_news), version 2.5.0
Calendar Base (cal), version 0.15.4

I implemented my news system and everything is just working fine. 
However, as soon as I install the extension "cal", I'm getting the 
following error message (shown three times):
Warning: Division by zero in 
/var/www/html/typo3/myinstance/typo3conf/ext/tt_news/pi/class.tx_ttnews.php 
on line 1153

After removing the extension "cal", everything is working fine again. 
However, my calendar is not shown any more on my page :-(.

Is that issue a problem of tt_news or of cal? Or of the combination of 
both? Any idea how that can be solved? Or at least can can I debug that 
issue. I'm somehow stuck at the moment.

Thanks for any hint

Regards

Andreas