The function addMathMML() fails because there is no MML2OMML_n.xsl file in the ..phpdocx_pro_conv/xsl folder (shouldn't this be included in the paid pro+ distribution?). Also at least on my localhost the syntax in CreateMath.inc ("load('../ ") was looking for that file in root, not phpdocx directory.
Your windows probably has the required file though, in the folder Program Files(x86)/Microsoft Office/Office
Mine was named MML2OMML.xsl (without the "_n").
Copy (not move!) that file into ..phpdocx_pro_conv/xsl
Then go edit (use a proper editor and be sure to keep utf-8 encoding; I use Bluefish) this line in CreateMath.inc -file (at ...phpdocx_pro_conv/classes ):
(of course use the correct xsl filename if your's is different)