Update: The following is obsolete. The missing file
OMXyhex.fd was added on MiKTeX update from Dec 5 2012.
Actually I must confess, that “yhmath” works with some issues (see MikTeX 2.9 can not find font yrcmex10 of yhmath package). I also noticed, that on CTAN there are two
yhmath.zip! The OP downloaded the other compared to me (link see below), and this is the one used in MiKTeX. So the problem seems to be a bug in
I let stand the following for reference reasons.
I would consider the missing font file
and the missing whole bunch of MetaFont files as a bug. It should be filed in the MiKTeX bug tracker.
All other files are installed in a full MiKTeX installation. You can get them with the Package Manager. Compared with my TeX Live installation in MiKTeX the type1 file is called
yhcmex.pfa, in TeX Live it is
yhcmex.pfb, but these are only variants, cf. https://en.wikipedia.org/wiki/PostScript_fonts.
If you downloaded the source files in the ZIP file (link: http://mirror.ctan.org/macros/latex/contrib/yhmath.zip), you must extract first into a temporary folder and then execute
tex yhmath.inson the command line:
which creates amongst some auxiliary files the font files, optionally followed by
latex yhmath.dtx, which creates the documentation.
You could temporarily Create a local texmf tree in MiKTeX and put the virtual font file
OMXyhex.fd into the folder
<localtexmf>\tex\latex\yhmath. The MetaFont files with extension
.mf belong into
For further action see MikTeX 2.9 can not find font yrcmex10 of yhmath package.