I'm using Windows 7 and when I try to install and this message appears: 
"An error ocurred: Could not retrieve the required installation files
For more information, please see the log file:
c:\users\.............\wubi-12.10-rev273.log"
The final part of the log - 
12-17 13:43 DEBUG  Distro:   checking whether F:\ is a valid Ubuntu CD
12-17 13:43 DEBUG  Distro:   parsing info from str=Ubuntu 12.10 "Quantal Quetzal" - Release i386 (20121017.2)
12-17 13:43 DEBUG  Distro:   parsed info={'name': 'Ubuntu', 'subversion': 'Release', 'version': '12.10', 'build': '20121017.2', 'codename': 'Quantal Quetzal', 'arch': 'i386'}
12-17 13:43 INFO   Distro: Found a valid CD for Ubuntu: F:\
12-17 13:43 INFO   root: Running the uninstaller...
12-17 13:43 INFO   CommonBackend: This is the uninstaller running
12-17 13:43 DEBUG  WindowsFrontend: __init__...
12-17 13:43 DEBUG  WindowsFrontend: on_init...
12-17 13:43 INFO   WinuiPage: appname=wubi, localedir=C:\Users\TASSO'~1\AppData\Local\Temp\pylED6A.tmp\translations, languages=['en_US', 'en']
12-17 13:43 INFO   WindowsFrontend: Operation cancelled
12-17 13:43 DEBUG  WindowsFrontend: frontend.quit
12-17 13:43 DEBUG  WindowsFrontend: frontend.on_quit
12-17 13:43 DEBUG  root: application.on_quit
12-17 13:43 INFO   root: sys.exit