stopping a service

I want to stop a running service (svnserve in this case) but when I run
service svnserve stop I get
Stopping svnserve
kill: 21415: Operation not permitted

I did try to use the 'force' option but that didn't work.

I'm running as root via ssh into a jail. Can anyone suggest what's causing this and how to overcome it?
I'm guessing you're not actually root? Root is always able to stop or even kill a service.
Where is that service running I wonder? Is it possible that you somehow picked up a service from either the host or the jail?