cannot kill process with kill -9

[Pieter Donche]

FreeBSD 7:
I have a mount_nfs process that refuses to get killed :
# ps -jaxw | grep mount
root   60342     1 60289 60289    0 D     ??    0:00.00 mount_nfs 
fenix.cmi.ua.ac.be:/opt /home/nfs/fenix/opt
This was called from a script, run bij root cron during the night
(does an NFS mount of a file system of a remote system and makes a backup)
I killed the parent processes: the shell executing the script, the script,
the mount process that calls mount_nfs, leaving me with that last
remaining process:

# kill -9 60342   doesn't do anything
# kill -9 -60289      (60289 is the PGID, see man kill)
doesn't do anything either

How to I get this process killed?