Unity won't start on login

[Pedro]

after login there is only a nautilus menu but there isn't the unity panel

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: unity 4.22.0-0ubuntu2
ProcVersionSignature: Ubuntu 3.0.0-12.19-generic 3.0.4
Uname: Linux 3.0.0-12-generic i686
ApportVersion: 1.23-0ubuntu2
Architecture: i386
CompizPlugins: [core,bailer,detection,composite,opengl,compiztoolbox,decor,resize,snap,imgpng,grid,move,unitymtgrabhandles,place,regex,mousepoll,wall,gnomecompat,session,vpswitch,animation,fade,expo,scale,ezoom,workarounds,unityshell]
Date: Fri Oct 7 10:40:09 2011
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Alpha i386 (20110705.1)
ProcEnviron:
 PATH=(custom, no user)
 LANG=it_IT.UTF-8
 SHELL=/bin/bash
SourcePackage: unity
UpgradeStatus: Upgraded to oneiric on 2011-09-22 (14 days ago)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.