I'll stay out of this one now, except for a couple of things:
One, xmplay.ini does exist, it is on my system as E:\Data\Programs\Un4seen\XMPlay\xmplay.ini, I can upload it, a screenshot of the file tree, a scanned printout of the contents of it, anything to prove that it does exist. It contains plugin settings, and could easily be expanded for other, advanced settings.
Two, I use IE which I either start by Win->P->I[->Enter], or by typing the adress in the address bar on my desktop (did you know you could have it there) and whacking return.
Three, the reason you need two versions of JavaScript is because Mozilla does not support DHTML, an official W3C standard, which is fully supported (beyond the original specification) by Microsoft, and which Mozilla *should* be made to support.