You very likely have an error somewhere in your entourage data... Address book or calendar. There MUST be a first, last OR company name in each record, to sync to the BB. If you have record(s) in entourage without data in one of those fields (or an odd symbol in one of those fields), fix that in entourage.
Likewise, attachments to calendar entries will trip up the BB also. Look through that data and see if you have any attachments in your calendar and delete those.
When you get your calendar and contacts clean, I am betting it will work. These two matters are the great majority of syncing errors.