Alternatively, you could unpack the zip file, move the existing moodle/filter/jsmath/jsMath/fonts folder into the unpacked jsMath folder, and then replace moodle/filter/jsmath/jsMath with the new jsMath folder.
It is also possible to go directly to jsMath's source CVS repository at sourceforge.net and load it from there. I give commands below that are for unix machines, so you may have to translate to whatever environment you are using.
cd moodle/filter/jsmath mv jsMath jsMath-old cvs -d:pserver:firstname.lastname@example.org:/cvsroot/jsmath login [press return when asked for a password] cvs -z3 -d:pserver:email@example.com:/cvsroot/jsmath co -P jsMath mv jsMath-old/fonts jsMathThis will use CVS to obtain the latest version of jsMath from sourceforge. The nice thing about this arrangement is that you can use
cd moodle/filter/jsmath/jsMath cvs updateto update to the latest jsMath, which is easier than downloading the zip file and unpacking it each time.
Once you have everything set up and working, you can delete the moodle/filter/jsmath/jsMath-old directory.
Hope one of those does the trick for you.
I wondered if you had thought about extending jsMath to writing chemical formulae. It would be a boon for us chemists.
Best wishes, Mike.