HTTP/1.1 404 Not Found Error Fix
Pulled from this forum: http://modmyi.com/forums/redsn0w/758303-fix-4-3-1-http-1-1-404-not-found-errors-cydia.html (worked as a fix for me on 08/02/2012)
General notes:
1.) Do not delete any directories *ever* (just files) or Cydia will fail to open
2.) Write down your custom repos as Cydia will restart with only the default installed
3.) If you can't find iFile (bigboss?), you will have to use mobile terminal or ssh
Here is the step-by-step:
1.) Download iFile from Cydia (not app store). It is $4, but has a free trial. Well worth it if you are uncomfortable with the command line (has a very nice GUI).
2.) Open iFile and navigate to /var/lib/apt/lists/partial/
3.) Delete all files in the directory (leave the directory or Cydia will crash)
4.) Navigate up one dir to /var/lib/apt/lists/
5.) Delete all files in this directory (the only thing this directory should contain is the empty partial folder)
6.) Navigate to /var/lib/cydia
7.) Delete metadata.plist
8.) Navigate to /etc/apt/sources.list.d/
9.) Delete all files in here including cydia.list
10.) Exit and respring
11.) Start Cydia and rejoice at the lack of 404 errors