Moved this question from the Adobe Reader Mobile community to Type & Typography since this question has nothing to do with Acrobat and/or mobile devices.
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To directly answer your question, Multiple Master Type 1 fonts cannot be installed nor are they supported on any recent version of Windows or for that matter MacOS. Multiple Master Type 1 fonts haven't been licensed by Adobe for over twenty years and as far as I know, no other font foundry has licensed them since then either.
Furthermore, no Adobe application other than Acrobat supports Multiple Master fonts at all. (In the case of Acrobat, there is support for existing PDF files that reference and have embedded Multiple Master fonts. These fonts are also used for substitutions for non-embedded fonts in some limited cases!)
Adobe's Multiple Master Type 1 fonts were succeeded by OpenType CFF font families containing multiple typefaces, each representing one of the fixed instances of the original Multiple Master versions.
You mentioned a “downloaded ZIP file” with the Multiple Master font you are trying to install. Since Adobe was the primary source of Multiple Master fonts in the day, so to speak, and we know of no “open source” or “shareware” Multiple Master fonts either from then or especially now, it is very likely that you downloaded something illegally posted. If you can provide the font name, we can confirm that for you! 😀
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