Outlook 2003 with Exchange 2003 Synchronisation Problem

[afischer]

Following Problem (on two of five laptops in our company):
I have Exchange Cache Mode enabled on the two laptops (Win2000,
Office 2003, latest Service Packs); the synchronisation starts, but
does not finish and the system hangs; the outlook.ost has then on both
systems 265KB; all other laptops (some vendor/version, same os, same office)
have no problems;
I have done the following without success:
- check all IP settings and domain settings (active directory)
- log on as administrator and synch administrator mailbox (this works fine
on the
other laptops without any problems)
- install latest Service Packs for Office and WIndows 2000
- delete outlook.pst
- delete and reinstall outlook2003
- reboot/ change permissions
Can anybody help me?