Keep in mind that MDX is no longer updated or supported and that it has various broken pieces in newer versions of mIRC. It's possible the icon part is one of those broken pieces. Considering MDX isn't updated anymore, you're better off writing new scripts using DCX. The syntax isn't exactly the same, but it's somewhat similar and it can do what MDX does, plus considerably more. And it's updated to work with newer versions of mIRC.
Also, most people here don't use MDX, so it isn't much of a surprise if you don't get many people responding about it. Few will go and try to learn it just to answer your question.
