Got the same problem here...
Have rebooted PC, checked time in BIOS to make sure it's correct, reloaded mIRC and still it's 1hr behind the windows clock.

I HAVE to ask... what POSSIBLE reason would mIRC need it's own region information or any other way of interpretting the time other than by simply using the windows system clock?!!

As far as I can see it's TOTALLY REDUNDANT... Not to mention damn annoying!