First time sync is ok - next time it halt

When I hard reset my PDA (Dell Axim 5) and connect to the PC and make a Sync
(Calender, Tasks and Contracts) every thing is fine and all is sync.

Then I remove the PDA and put it in the cradle again (connection with USB) -
it starts to sync but before it is done with finding new item it halts and
get me an error.
The try to sync is also where slow.

If I hard reset the PDA and only sync tasks and contract I can sync also
after the first sync - so the prob must bee in sync the calender after the
first time were everything is fine.

Any1 know what I should look after in the calendar - witch make it stop ??

Outlook 2003 on XP SR2
Windows Mobile - PDA