The XHTML files produced by MathCast are compatible with Mozilla, Firefox, and Netscape browsers, which have internal support for MathML.
Internet Explorer, on the other hand, requires a program update to enable displaying MathML. One such application is Design Science's MathPlayer, available at http://www.dessci.com/en/products/mathplayer. If you want to view MathCast's equation lists in Internet Explorer:
Make sure you save your files with the hexadecimal XML layout. This option can be set in the Settings Screen. Edit the XHTML file with WordPad and replace the <!DOCTYPE html PUBLIC '-//W3C//DTD XHTML 1.1 plus MathML 2.0//EN' 'http://www.w3.org/TR/MathML2/dtd/xhtml-math11-f.dtd' [<!ENTITY mathml 'http://www.w3.org/1998/Math/MathML'>]> with <?xml-stylesheet type="text/xsl" href="http://www.w3.org/Math/XSL/pmathml.xsl"?>
You can download pmathml.xsl and place it in the same folder as your XHTML file. In that case, just write <?xml-stylesheet type="text/xsl" href="pmathml.xsl"?>