doc-src/TutorialI/tutorial.tex

 \documentclass{article}
 \newif\ifremarks
 \remarkstrue          %TRUE causes remarks to be displayed (as marginal notes)
 \usepackage{cl2emono-modified,isabelle,isabellesym}
 \usepackage{latexsym,verbatim,graphicx,../iman,../extra,../ttbox,comment}
-\usepackage{proof,amsmath}
+\usepackage{../proof,amsmath}
 \usepackage{../pdfsetup}    %last package!
 
 %\newtheorem{theorem}{Theorem}[section]
 \newtheorem{Exercise}{Exercise}[section]
 \newenvironment{exercise}{\begin{Exercise}\rm}{\end{Exercise}}