[TYPO3-calendar] Call to undefined method TYPO3\CMS\Cal\Model\Pear\Date\Calc::daysToDayOfWeek()

[Bernd Pier]

Hi Liste,

i`ve got a Problem with this Typoscript Option
plugin.tx_cal_controller.view.day.dateFormatDay
on my local Machine it works very fine, but on the Live-System i got 
this Error:
Call to undefined method 
TYPO3\CMS\Cal\Model\Pear\Date\Calc::daysToDayOfWeek()

Error thrown in file
/home/celseo/htdocs/celseo/typo3conf/ext/cal/Classes/Model/Pear/Date/Calc.php 
in line 364.

This is curious cause the Extension on the Live-System is the same as on 
my local Machine.

Can anybody help me?

Thx

Bernd