The problem is simple, what happen here is that $network" does not exists, mirc would said it if you have checked the "identifier warning option" in the mIRC script editor, but since there's a '.', it quiet the output and you don't see anything.
The question is why is there a dot since /writeini does not output a message that could be annoying (like /timer) ? I've seen so many script (whole script or not) do this on several command, always wondering why they wanted to hide errors...