How can I create an index with the memoir document class? I always get an error message.
\documentclass[10.5pt,a4paper,oldfontcommands]{memoir}
\usepackage[polutonikogreek, latin, english, french, ngerman]{babel}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{microtype}
\usepackage[dvips]{graphicx}
\usepackage{times}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsthm}
\usepackage{latexsym}
\usepackage{stmaryrd}
\usepackage{enumerate}
\usepackage{nicefrac}
\usepackage[all]{xy}
\usepackage{tabularx}
\usepackage{pst-plot,pstricks}
\usepackage{varwidth}
\usepackage{thmtools}
\usepackage{enumitem}
\usepackage{geometry}
\usepackage{float}
\usepackage{siunitx}
\usepackage{natbib}
\usepackage{graphicx,xcolor}
\usepackage{epstopdf}
\usepackage{pdfpages}
\usepackage{epsfig}
\usepackage{filecontents}
\usepackage{transparent}
\graphicspath{{img/}}
\usepackage{pgfplots}
\def\FunctionF(#1){(#1)^3- 3*(#1)}%
\usepackage{url}
\floatstyle{boxed}
\restylefloat{figure}
\renewcommand{\listfigurename}{Abbildungen}
\usepackage[breaklinks=true,colorlinks=true, linkcolor=black,urlcolor=black,citecolor=black, bookmarks=true,bookmarksopenlevel=2]{hyperref}
\usepackage{geometry}
\geometry{total={210mm,297mm},
left=20mm,right=20mm,
bindingoffset=10mm, top=20mm,bottom=20mm}
\OnehalfSpacing
%%% CHAPTER'S STYLE
\chapterstyle{lyhne}
%%% STYLE OF SECTIONS, SUBSECTIONS, AND SUBSUBSECTIONS
\setsecheadstyle{\Large\bfseries\sffamily\raggedright}
\setsubsecheadstyle{\large\bfseries\sffamily\raggedright}
\setsubsubsecheadstyle{\bfseries\sffamily\raggedright}
%%% STYLE OF PAGES NUMBERING
\pagestyle{plain}
\makepagestyle{plain}
\makeevenfoot{plain}{November 2016}{}{\thepage}
\makeoddfoot{plain}{November 2016}{}{\thepage}
\makeevenhead{plain}{\underline{Schweizer Jugend Forscht}}{}{\underline{Potz Blitz - Gewitter in Theorie und Praxis}}
\makeoddhead{plain}{\underline{Schweizer Jugend Forscht}}{}{\underline{Potz Blitz - Gewitter in Theorie und Praxis}}
\maxsecnumdepth{subsection} % chapters, sections, and subsections are numbered
\maxtocdepth{subsection} % chapters, sections, and subsections are in the Table of Contents
\begin{document}
Hello
\end{document}

10.5ptis not a valid option formemoir. – Peter Wilson Nov 05 '16 at 19:03