[horde] Problem with the alarm cronjob

[Volker Then]

Hi,

executing the alarm script /horde/scripts/alarms.php gives a warning,  
but only when there
are due tasks somewhere in the past:

Warning: array_keys(): The first argument should be an array in
/var/www/html/horde/nag/lib/Driver.php on line 322

The horde portal itself says

Warning: array_keys(): The first argument should be an array in
/var/www/html/horde/nag/lib/Driver.php on line 321

Any idea if I missed some upgrade instructions?

Regards.

Volker