This is pdfTeX, Version 3.1415926-1.40.10 (TeX Live 2009) (format=pdflatex 2009.11.7) 3 OCT 2012 13:07 entering extended mode \write18 enabled. %&-line parsing enabled. **1.1.circular-units.tex (./1.1.circular-units.tex LaTeX2e <2009/09/24> Babel and hyphenation patterns for english, usenglishmax, dumylang, noh yphenation, german-x-2009-06-19, ngerman-x-2009-06-19, ancientgreek, ibycus, ar abic, basque, bulgarian, catalan, pinyin, coptic, croatian, czech, danish, dutc h, esperanto, estonian, farsi, finnish, french, galician, german, ngerman, mono greek, greek, hungarian, icelandic, indonesian, interlingua, irish, italian, ku rmanji, latin, latvian, lithuanian, mongolian, mongolian2a, bokmal, nynorsk, po lish, portuguese, romanian, russian, sanskrit, serbian, slovak, slovenian, span ish, swedish, turkish, ukenglish, ukrainian, uppersorbian, welsh, loaded. ! Undefined control sequence. l.5 \subsection {Circular units} ? ! Emergency stop. l.5 \subsection {Circular units} End of file on the terminal! Here is how much of TeX's memory you used: 5 strings out of 493848 170 string characters out of 3149207 48936 words of memory out of 3000000 3381 multiletter control sequences out of 15000+200000 3640 words of font info for 14 fonts, out of 3000000 for 9000 714 hyphenation exceptions out of 8191 5i,0n,1p,66b,8s stack positions out of 5000i,500n,10000p,200000b,50000s ! ==> Fatal error occurred, no output PDF file produced!