Schedule duplicates

Hello,

I've added a few days ago an entry in my today planner page like this :

@19:00 do something

and it appeared in schedulerr too !

But now for each emacs restart, it puts one more entry in Scheduler 
(a duplicate). Any ideea why this happens ?

GNU Emacs 22.0.50.1 / Planner 3.40

Regards,
Cezar