FYI, Common.attrib is defined in xhtml-attribs-1.xsd,
which is included by xhtml-framework-1.xsd,
which is included by xhtml11-modules-1.xsd,
which is included by NeatHtml.xsd,
which is what mojoportal actually references.
mojoportal expects all of those files to be under APPROOT/NeatHtml/schema/ which in your case appears to correspond to:
E:/Applications/MojoPortalApp/mojoportal/Web/NeatHtml/schema/xhtml-inlphras-1.xsd
Can you confirm that all of the above files are present in your installation?
--Dean