The 5th item in the n2 line refers to the look up method in the Local Info section of the Options/Connect dialog. I can't think of any reason why it should cause mIRC to crash, the same method has been used to look up the local host and ip address for many years.
I tried turning the local info setting on and off in mIRC and experienced no crashes here, also running under Windows XP Pro SP1 with all of the latest patches, including KB840374. At a guess, the issue may be due to a conflict of some sort in your Windows installation relating to network/firewall/anti-virus/etc. software.
If you install a new copy of mIRC into a clean empty folder with no scripts, etc. and then test different Local Info settings, does this clean copy of mIRC also crash?
