Navision 4.0 Server Service Crashes

Hi, we have installed Navision 4.0 server on a MS 2000 server. Whenever we try connecting to the server using Windows Authentication, the service on the server stops. However, we have no problem connecting to the server using database authentication. If we run the server from the command line prompt both database authentication and windows authentication work. Any ideas? Same experiences? Thx. Jan Grefe