Pwnage Tool 4.3.3 "i haz fail"...Why?

[iTouch-Warrior]

Hello everyone! I've been facing problems with Pwnage Tool since version 4. Everytime I try to make a custom ipsw it shows the "i haz fail" message and the log ends with this:

Attaching root filesystem to '/Volumes/Durango8J2.N90OS'.

I'm no n00b when it comes to jailbreaking (I've been jailbreaking since iOS 3.0), but I haven't been able to use Pwnage for anything useful. I had to use Sn0wbreeze last time, but I have an iMac...I really don't like having to borrow a PC just to jailbreak my iPhone. And yes, I know, redsn0w works great, but I want to preserve my baseband.

Is there anything I should do/should have done to make pwnage tool work? Any ideas?

I believ there must be something wrong with my iMac because every Pwnage Tool since version 4.0 has failed everytime, expert mode or not, it just fails...

Thanks in advance.