Do you have BES 4.0 - if so you will not want to use the desktop mgr intellisynch settings. Once you do the enterprise activation it sets-up wireless synch automatically. check the options menu under each item on your bb tasks, notes, calendar, contacts. In each options menu is the ability to select wireless synch to "yes" right from the blackberry. If you use intellisynch and synch with the server it will override the wireless synch settings and set them to whatever they are in the configure PIM area I believe...i.e. it breaks it..

hope this helps...with BES 4.0 intellisynch is not needed anymore..yippie!