Please Help: After Downgrading, Terminal cannot execute binary file

I have an iphone 3G and a mac osx 10.4.11.

After upgrading to 3.1 and losing my tethering, i decided to follow the steps from BENM.AT website.

I downloaded and installed the iRecovery and LibUSB, put my phone in dfu mode and re-installed the previous software but when it came to the step for me to open my terminal and put in the first command 'iRecovery -s' it tells me '-bash: /sbin/iRecovery: cannot execute binary file'.

So i don't know what i need to get past this problem and continue putting the rest of the commands into the terminal to reboot my phone.

Can anyone knowledgeable please help?

 

anyone?

..before i try throwing my phone against the wall.