The information you have given tells me that you have 14 scripts loaded.
Unload all of those scripts or install mIRC to a clean directory (no scripts, no add-ons).
Additionally I have to wonder where you got your copy of mIRC, since the signature on the executable failed.
You should download mIRC from here
After doing this see if the same thing happens. If it doesn't, then it is a matter of a script that you have loaded, as I originally suspected.