Hey i got a suggestion for ya, why dont you click on them links and actually read what it says there.

The fault is in the router not in mirc, the router is shutting down internet access becuase of what is being said, mirc just happens to be the client that looses connection becuase its the one your using.

Oh and what linksys router u got, becuase its not effecting either of mine, i just tried it on myself so im sure of that. mines are WAG54G and WRT54G latest non beta firmware on each.