XeTeX export works after removing the unnecessary
hyperref package option 'hypertex'.
\else % if DVI
-\usepackage[colorlinks=true, hypertex]{hyperref}
+\usepackage[colorlinks=true]{hyperref}
\fi
\else % if DVI
-\usepackage[colorlinks=true, hypertex]{hyperref}
+\usepackage[colorlinks=true]{hyperref}
\fi
\else % if DVI
-\usepackage[colorlinks=true, hypertex]{hyperref}
+\usepackage[colorlinks=true]{hyperref}
\fi
\else % if DVI
-\usepackage[colorlinks=true, hypertex]{hyperref}
+\usepackage[colorlinks=true]{hyperref}
\fi