Go to terminal as ROOT:
devel-su
rootme

1. Restore your calendar icon:
mv /usr/share/applications/.calendar.desktop /usr/share/applications/calendar.desktop

2. restore your second app by reinstalling (this not delete your info)

3. Go to terminal as ROOT again:
devel-su
rootme
rm -f /home/user/.config/meegotouchhome-nokia/laun*
/sbin/reboot

this will reboot your phone and should to resolve your problem with duplicated icons.. But this action will disorganize all your icons on the homescreen..