This may help, I did something similar:
I know that the trouble is with: i <=8 Should it be rewritten as: i <= 8
Yes. That's HTML for less than.
I'm assuming that I can perform this operation without connecting the matrix to the Uno by holding the positive lead of my multimeter on any matrix pin and then touching the negative lead to any other matrix pin ... but nothing ever lights up.
What mode is your meter on? You probably need ohms mode so it puts out a voltage. Also try reversing. If you have the lead the wrong way (for a particular pin) it will never light up.