How to fix error 1604 on iTunes?

So I have an iphone 3gs and i want to use this thing called whited00r but every time I try and restore my iPhone, I keep getting an error: P
Can somebody please tell me how I can fix this?

Listen if this issue is not resolved by USB isolation troubleshooting then try these steps to resolve the issue:

1.Connect the device to iTunes, confirm that the device is in Recovery Mode. If it's not in Recovery Mode, put it into Recovery Mode.
2. Restore and wait for error 1604.
3. When prompted, click OK.
4. Close and reopen iTunes while iPhone remains connected.
5. IPhone should now be recognized in Recovery Mode again.
6. Try to restore again.

May be it helpful for you…