[TYPO3-ttnews] problem with datemenu of tx_news

[bernd wilke]

my configuration are three plugins into one page:

plugin list template1
plugin datemenu
plugin list template 2


As soon as I follow a link of the datemenu I get the error:
----------
#1297759968: Exception while property mapping at property path "":Could 
not find a suitable type converter for "array|null" because no such 
class or interface exists. (More information)

TYPO3\CMS\Extbase\Property\Exception thrown in file
/var/www/vhosts/typo3/typo3_src-6.1.1/typo3/sysext/extbase/Classes/Property/PropertyMapper.php 
in line 120.
---------

How can I solve this?
How can I debug where it goes wrong?


bernd
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