Sounds like there's something about your bot that's mirc 6.14 specific. There have been some minor changes in mirc 6.15 which may have affected it. Check the
versions.txt to see if something in there might be the possible cause.
I use mirc 6.15 with windows 2k pro and some of my own customized scripts and never had any problems except 1 and I checked the
versions.txt and sure enough a bit of coding change was the culprit - I've since deleted that particular script and made a better one.
If the problem doesn't resolve and you like your bot - go back to mirc 6.14 or get a new bot (or change it yourself if possible).
Talea