Need help with ICloud settings to avoid duplicate entries.

[lv1]

I am looking at my ICloud calendar and there are duplicate entries. What am I doing wrong?? Here is what I am doing.

. I synch to my work computer running XP and Outlook (on Exchange server), only synching the calendar. I have only 1 calendar. This synch gets my IPhone calendar updated.
. On the Itunes Summary page I have "back up to ICloud checked).

. On the IPhone, ICloud settings, I have ICloud Backup enabled and I have the calendar unchecked.