umount(ing) LVM ext3 partition problem

I am using RHEL4 OS and the problem i have is that when i try to umount an LVM implemented partition after checking the properties of the mounted folder it gives the error of device busy .
things iam not doing : iam not in the mounted woulder either by shell or by GUI.
thing iam not trying do : using fuser -k or fuser --signal : because iam afraid it will kill a process used by the other process or resource.
iam not even sure if its an LVM bug or other problem . iam using RHEL4 default packages.
thanx in advance.

what about fuser without "-k"? Does it show any process?

yes "fuser /mnt" shows the process ID=3251.

and "ps -ax" reveals

 PID TTY      STAT   TIME COMMAND
 3251 ?        S      0:00 /usr/libexec/gam_server

i dont know how to approach this problem can anyon guide me with this.

kill -9 3251 
ps aux|grep 3251
umount -f /thefilesystem

gam_server is a gnome file monitor. Don't worry about it.

gee thanks 'grial.'