You did not mention the version of moodle and when/how the tinymath editor was added but I can think at least one possible reason for this kind of issues that came visible about 4 months ago - and you might see it even in http://www.dragmath.bham.ac.uk/demo.html with the latest versions of java - at least in firefox.
For some reason if dragmath is initialized with code like
<applet width="540" height="333" archive="DragMath.jar" code="Display.MainApplet.class" codebase="applet" name="DragMath">
<param value="en" name="language" />To use this page you need a Java-enabled browser. Download the latest Java plug-in from <a href="http://www.java.com/">Java.com</a>
dragmath does not work anymore - it used to work this way a couple of months ago with the latest versions of dragmath...
The plugins were last time upgraded 3 months ago and I suppose most tinymath plugins that use dragmath should be located in folder lib/editor/tinymath/tiny_mce/3.4.9/plugins and for example dragmath plugin there (dragmath.php) is using "the old dragmath version style code" like
codebase="<?php echo $CFG->httpswwwroot.'/lib/dragmath/applet' ?>"
<param name="language" value="<?php echo $lang; ?>" />
<param name="outputFormat" value="MoodleTex" />
<?php print_string('dragmath:dragmath_javaneeded', 'editor_tinymce', '<a href="http://www.java.com">Java.com</a>')?>
that should work ok with the version of dragmath included to moodle 2.X.
So my guess is that you might have some more than 3 months old version of mpluga.zip or mplugb.zip or the old plugin files could be cached - for example if XAMPP has in php.ini
eaccelerator.enable = "1" (this can be set to 0 to disable eaccelerator)
(default value for Xampp is 1)
which could prevent upgrading of old php files to take action.
PS. I am sorry that I really have not checked any files of the packages during the past 3 months - in fact I have not even responded to any messages and questions lately to take some real "holiday" after several years of "moodle dependence"...