Problem with CUDA 3.0 on Snow Leopard

I am a newbie and totally no knowledge in coding and I have a problem regarding the installation of CUDA. So I hope somebody could guide me along.
I was trying to install a rendering software.
The specific instruction was to install the CUDA 3.0 driver followed by the CUDA 3.0 Toolkit, and lastly the software.
By mistake I did not follow the sequence and now software cannot run.

Their admin tried to help me by instructing me to link the files via the Terminal window. Below is the result:

The first attempt resulted in ‘No such file or directory’ found. Then I was advised to run the ‘sudo’ command,
and for some reason, when I am asked to enter the password, nothing happens when I hit the keyboard (in other words I am not able to input any characters).
I have administration rights to the system.

Is there something I had done wrong?
What should I do in order to be able to key in my password into the Terminal window?

Lastly, I was also advised to uninstall CUDA 3.0 and reinstall everything according to the sequence.
But how does one uninstall the 3.0 CUDA drivers and Toolkit?


Details of my system is as follows:
Mac Pro 2 x 2.8GHz Quad Core
nVidia GeForce 8800 GT

By the way, I had also installed XCode from the Snow Leopard installation disc as advised by one of the Octane forum member.
But it still did not work for me :-(

OK, I now know I have to log in as the root user to key in my root user password in the Terminal.
CUDA files are still not found.

Any idea if one can roll back to pre-CUDA status or how to uninstall/remove CUDA from my system?