[horde] Fatal error when running login tasks

[Luis Felipe Marzagao]

Hello:

Today (first day of the month), when running login  tasks, I got this:

Fatal error: Call to a member function push() on a non-object in 
/var/www/horde/imp/lib/LoginTasks/Task/PurgeSentmail.php on line 74

The address was horde/services/logintasks.php?app=imp

Horde (horde) 5.0.3
Mail (imp) 6.0.3

Thanks,
Luis Felipe