maru@maru-laptop:~/compiz$ sudo apt-get update
Password:
Get:1 http://it.archive.ubuntu.com feisty Release.gpg [191B]
Ign http://it.archive.ubuntu.com feisty/main Translation-en_US                
Get:2 http://security.ubuntu.com feisty-security Release.gpg [191B]           
Ign http://security.ubuntu.com feisty-security/main Translation-en_US         
Ign http://it.archive.ubuntu.com feisty/restricted Translation-en_US
Ign http://it.archive.ubuntu.com feisty/universe Translation-en_US
Ign http://it.archive.ubuntu.com feisty/multiverse Translation-en_US
Get:3 http://it.archive.ubuntu.com feisty-updates Release.gpg [191B]
Ign http://it.archive.ubuntu.com feisty-updates/main Translation-en_US      
Ign http://it.archive.ubuntu.com feisty-updates/restricted Translation-en_US
Hit http://it.archive.ubuntu.com feisty Release
Ign http://security.ubuntu.com feisty-security/restricted Translation-en_US   
Ign http://security.ubuntu.com feisty-security/universe Translation-en_US
Ign http://security.ubuntu.com feisty-security/multiverse Translation-en_US
Hit http://it.archive.ubuntu.com feisty-updates Release              
Get:4 http://download.tuxfamily.org feisty Release.gpg [189B]                 
Hit http://security.ubuntu.com feisty-security Release               
Ign http://download.tuxfamily.org feisty/eyecandy Translation-en_US  
Hit http://it.archive.ubuntu.com feisty/main Packages               
Hit http://it.archive.ubuntu.com feisty/restricted Packages          
Hit http://it.archive.ubuntu.com feisty/restricted Sources           
Hit http://it.archive.ubuntu.com feisty/main Sources
Hit http://it.archive.ubuntu.com feisty/multiverse Sources
Hit http://security.ubuntu.com feisty-security/main Packages
Hit http://it.archive.ubuntu.com feisty/universe Sources
Hit http://it.archive.ubuntu.com feisty/universe Packages
Hit http://it.archive.ubuntu.com feisty/multiverse Packages
Hit http://it.archive.ubuntu.com feisty-updates/main Packages        
Hit http://it.archive.ubuntu.com feisty-updates/restricted Packages  
Hit http://it.archive.ubuntu.com feisty-updates/main Sources         
Hit http://it.archive.ubuntu.com feisty-updates/restricted Sources   
Hit http://download.tuxfamily.org feisty Release                     
Err http://download.tuxfamily.org feisty Release
  
Hit http://security.ubuntu.com feisty-security/restricted Packages
Hit http://security.ubuntu.com feisty-security/restricted Sources
Hit http://security.ubuntu.com feisty-security/main Sources
Hit http://security.ubuntu.com feisty-security/multiverse Sources
Hit http://security.ubuntu.com feisty-security/universe Sources
Hit http://security.ubuntu.com feisty-security/universe Packages
Hit http://security.ubuntu.com feisty-security/multiverse Packages
Get:5 http://download.tuxfamily.org feisty Release [14.2kB]
Ign http://download.tuxfamily.org feisty Release
Hit http://download.tuxfamily.org feisty/eyecandy Packages
Hit http://download.tuxfamily.org feisty/eyecandy Sources
Fetched 14.4kB in 1s (8818B/s)
Reading package lists... Done
W: GPG error: http://download.tuxfamily.org feisty Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 2D6CFB44DD800CD9
W: You may want to run apt-get update to correct these problems

maru@maru-laptop:~/compiz$ apt-get update
E: Could not open lock file /var/lib/apt/lists/lock - open (13 Permission denied)
E: Unable to lock the list directory
maru@maru-laptop:~/compiz$