If you have the computer with the iTunes library the iPhone 4 synced with, you can reset the passcode by continually entering the incorrect passcode until the iPhone needs to be connected to iTunes. The iTunes that the iPhone once synced with will reset the passcode. Or if you just want to get a usable phone right away and don't mind losing what's currently on the iPhone 4, put it into DFU mode (Google it) and restore it.
The computer I used was sold, so I don't have it anymore.
Yes. That is the question. The screen is blank like the instructions said, but i still get the ineligible error message.
Make sure you are logged in as administrator
Hold down COMMAND + SHIFT keys and press G
Enter /private/etc/ in the field and press Go
Find hosts file in the directory
Drag the file to your desktop
Open it in text editor
Remove the line that has gs.apple.com entirely or put a # at the beginning of it to comment it out
Save the file
Drag it back to the /private/etc/ folder
Enter your username and password to authenticate
Locate the hosts file in one of the following directories:
Windows 95/98/Me c:\windows\hosts
Windows NT/2000/XP Pro c:\winnt\system32\drivers\etc\hosts
Windows XP, Vista, 7 c:\windows\system32\drivers\etc\hosts
Right click on it and choose Open With then click on Notepad
Remove the line that has gs.apple.com completely and save the file