I'm not sure what "full language support" means with regards to XP. Are you referring to the East Asian Languages checkbox under "Regional and Language Options"? If so,
this option causes GDI drawing errors and thus can't be used.
Regarding reproducing the problem: I'll spend some time working on this tonight, barring interruptions at work. It should be easily reproducible using VMware given the nature of the problem. I'll document all steps, from OS install to mIRC being run.
