seems to be a bug in the way /run handles paths starting with .. (directory up).
for instance i've had $isfile(..\somedir\somefile.ext) return $true, whereas /run ..\somedir\somefile.ext gives an error: * /run: unable to open '..\somedir\somefile.ext'

forgot to mention, i'm using win xp pro sp1 and mirc 6.03.

I assume you are trying to get a file director in the same folder mirc itself is listed? Ex: C:\mirc\ and trying to read C:\texts\myfile.txt I would just recomment trying a $remove($mircdir, mirc\) then using that as a directory prefix.. Easy enough to execute, and cshouldn't cause any problems. This will give you the C:\mirc\ or C:\Program Files\mirc\ then remove the folder name..