moving SL licenses - port 5972 error / manual deactivation

We’re in the process of replacing two of our lab computers (Win XP) both of which have SL 4.5 installed. i have attempted to deactivate the SL licence codes on the old pcs but get the ‘port 5972 not open’ error message.

I added port 5972 as an exception in windows firewall but the error remains. Is it possible to manually deactivate the licence codes on the old pcs so that we can re-use the license codes on the two replacement computers?

I will contact you via private message regarding your license activity.