Hello have you tried deleting your partnership and resyncing each item one by one? I ask because I had the same issue and once I deleted the partnership and set each item to sync seperately I have not had the issue since. I setup my phone but synced nothing, then once the partnership was saved I changed it to sync with contacts, ran sync, then setup to sync the calendar,save the change, run sync again. I did this until all that I wanted synced up was syncing up without issue. You can also go to review the sync errors and see if a calendar item is causing the issue and if you delete the issue in conflict and after a successful sync, you can always go back and add it later if need be and it should sync fine on both PCs once they are in sync
It could be something as simple as you have the item listed one way on your PC and then the secretary has the same item on her PC and it can cause a conflict to occur on the mobile phone.
Also if you are syncing up with 2 PCs you may want to download ODIR for your PCs if you use MS Outlook which removes duplicate items. Syncing with 2 PCs periodically creates duplicate entries for Outlook and it is a known issue by Microsoft as well. ODIR is a free item with no spam attached and works with Outlook 2007 as well.
http://www.vaita.com/ODIR.asp . Hope you get it worked out
