I had heard of a Whilefix.dll awhile back that was used on what seemed to be an mp3 snippet. Might be worth taking a look at; although I don't know that a small snippet such as this would be suffice motivation to download it. Apparently it prevents mIRC from freezing or 'hanging' in large while loops, and judging from the mass of while functions I'd say it could be of use.
EDIT: Found it. Check the description for the link. http://www.hawkee.com/snippet/8521/