Can't jailbreak!

I have iphone 4 (iOS 4.1) and I've tried jailbreak with:

1- limera1n
2- greenpois0n
3- redsn0w_win_0.9.6b2


but each time it occurs a special error according to the software:

1- limera1n: continue to remaining on "waiting for device" section ...

2- greenpois0n: I do the process (2, 10, 15 seconds) but it says to try again (nothing happens!)

3- redsn0w_win_0.9.6b2: On the first page I have to browse for "corresponding IPSW for your CURRENT firmware" and I don't know what to do

:confused::(:mad:

For Redsnow, you need to download and select 4.1 even thought say "Current firmware..."