[TYPO3-calendar] Use of a cal service

[Chris Müller]

Hello,

now I made a plugin with the following code:

require_once t3lib_extMgm::extPath('cal') . 
'controller/class.tx_cal_api.php';

class tx_test_pi1 extends tslib_pibase {
   public function main($content, array $conf) {
     $calApi = t3lib_div::makeInstance('tx_cal_api');
     $calApi = &$calApi->tx_cal_api_without(62);
   }
}

and get the error:
Call to a member function versionOL() on a non-object in 
/usr/local/share/typo3/typo3_src-4.7.5/typo3/sysext/cms/tslib/content/class.tslib_content_content.php 
on line 114

If I dump the $calApi variable I am getting the object with the 
configuration and the various objects and the mentioned error.

Any help will be appreciated.

Regards,
Chris.