"Disk is(ALWAYS)busy

[dimitris]

Everytime i'm trying to use Disk Utility it's imposible to proceed to any kind of task,like partitioning or erasing...It always says that i can't,disk is busy.tried to unmount but i got the same

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: gnome-disk-utility 3.0.2-1ubuntu2
ProcVersionSignature: Ubuntu 3.0.0-12.20-generic 3.0.4
Uname: Linux 3.0.0-12-generic i686
ApportVersion: 1.23-0ubuntu4
Architecture: i386
Date: Thu Nov 10 22:46:04 2011
ExecutablePath: /usr/bin/palimpsest
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release i386 (20111012)
ProcEnviron:
 PATH=(custom, no user)
 LANG=el_GR.UTF-8
 SHELL=/bin/bash
SourcePackage: gnome-disk-utility
UpgradeStatus: No upgrade log present (probably fresh install)