Ok - so there's something not 100% with networking in general and that
would explain the failure of getting the wireless printer to connect.

Next question is whether you got any error messages from Mint when you
tried to access the network or did it just ignore you ? Usually when
accessing networks for the first time Ubuntu will prompt you to get
the required packages for this - have you ever got anything like that
from Mint 11 and what was the procedure on the other Ubuntu 11.04
boxes when accessing the printer / network shares for the first time ?