I would guess some other widget blocks it! Have you tried to set it up on another desktop or a desktop without anything on but the MP widget?

What does a hildon-home restart do?

cmd there is:

#!/bin/sh
dsmetool -k /usr/bin/hildon-home
sleep 10
dsmetool -t /usr/bin/hildon-home

-k kills it and detaches from watchdog
-t starts it attached to watchdog

if you just kill hildon-home once by hand (not with dsmetool but kill or killall) it does restart itself, if you do that several times in a row the watchdog will think there is something wrong and will restart the device