So it looks like you have jails possibly running but for some odd reason they are not recognized, very odd.
Did you try
Code:
cd/mnt/WinShare/jails
rm -rf owncloud_1
and then reboot and do it again if needed to clean up any remaining files?
Option 1: Disable the plugin from within the jail...
Code:
cd /mnt/WinShare/jails/owncloud_1/etc
mv rc.conf rcold.conf
or you could just delete rc.conf, then reboot and try to delete the owncloud_1 directory.
Option 2: Try to identify the services running and stop them...
I'm in new territory as I've never experienced this before but you could try this:
Now look for the IDs that are associated with a path to your jails, write down the ID numbers. Next you will pkill each ID number. For example:
Hopefully you are able to kill a process which is keeping you from removing the directory. You may not be able to stop all the suspect processes but don't let that stop you from trying to delete that directory.
Option 3: Brute Force Attack...
Also, you can go into the jail directory /mnt/WinShare/jails/owncloud_1/ and just start deleting files. Eventually you are likely to delete something that will cause the program to fail during a reboot and once that program isn't running again, you should be able to delete it all. This could take a while. I would focus on the etc/rc.conf