Here's another weird Symbian thing. If you are trying to iSync your calendar and you get "App. closed DosServer", try out the helpful advice from this posting:
If you're using a Mac, check to see if you have any published calendars.. and whether or not you created this calendar AFTER you paired the phone. Now if that's the case.. go to your phone settings in iSync and change the settings from all to selected.. deselect the published calendars and try iSync again. This resolved my errors. After the first sync then simply reselect all and you should be fine. Sounds illogical.. but it worked.. have NO CLUE why?