1. Make sure you have the
latest version of Internet Explorer.
2. Make sure you have all available
Windows updates.
3. Make sure you have the
latest version of mIRC.
Make sure your mIRC directory is "normal" - i.e. it's not in a locked folder or anything like that. Most popular directory is C:\Program Files\mIRC or C:\mIRC. If you don't know the mIRC directory you can type
//echo $mircdir whilst in mIRC to find it out.
If you've done the above, then it may be an IE issue. Try Microsoft's
Support site and use the various methods to obtain assistance

G'luck!
Regards,