IIS Admin Service will not stop

I cannot get the IIS Admin Service to stop on W2003 Server.

Error 1921. Service 'IIS Admin Service' (IISADMIN) could not be
stopped. Verify that you have sufficient privileges to stop system
services.

I have also enabled IWAM_CENTRALIT1, which was disabled, but without
success:
IISADMIN service found that account IWAM_CENTRALIT1 is disabled. Some
IIS functions can fail for this reason.

I'm using the local System account on the server, restarting this
service is working but it will not stop.

Is there anything to do before trying to stop this service.

Thanks in advance.
Jaap