[otrs] OTRS V2.1.6: no Emails with Windows Exchange

Hello to all, trying to get comfortable with OTRS, I used to test version 2.0.4 with Windows2003 and Exchange Server 2003 during the last weeks. Receiving and sending Emails went fine. I had the old version completely uninstalled recently and version 2.1.6 installed via the Windows installer. Now I can't any longer receive emails from or send to the Exchange Server although I use the same config.pm as before. I repeated the installation with the default config.pm but got the same results. There might be some incomplete cron-jobs for Windows, I suppose, but I can't judge this actually since I'm a real novice. Can anybody help me with some hints how to utilize CRONw correctly? Thanks in advance Uli