Much thanks to The Monk!!!!
Just wanted to 'publicly' display my thanks to Monk for helping me and a gaming buddy of mine rectify a situation where my buddy couldn't get into my room for an MP game on ICO.
Monk provided us with a link to his guidebook as well as helpful in-chat technical advice. I don't think there wa anything wrong on my end regarding my router, NAT settings, security settings (made sure to leave Sins as allowed) but there was somethign wrong with my buddy's set-up which he later rectified and played his first ever Sins on-line game. Not only that but he won as well!
Thanks again, Monk!