mad.ex error for exchange 5.5

Hi,

I am receiving the foloowing error when starting the Microsoft System Attendant Service:

mad.exe application error; the application failed to initialized properly (0xc0000005) and after clicking on the ok button.

the eventviewer reports:
The Microsoft Exchange System Attendant service failed to start due to the following error:
The service did not respond to the start or control request in a timely fashion.

:( Many muchu help needed :)

Thanks.

Leopold