Hans et al, When we discovered that \column doesn't work reliably with \startcolumns[n=2] ... \stopcolumns, we made some changes to our style files: %\setupcolumns % [tolerance=stretch, % balance=yes, % blank=flexible, % rule=off, % distance=2.5em] \definecolumnset[exercises][n=2] \setupcolumnset [exercises] [distance=2.5em, balance=yes] \definecolumnset[answers][n=2] \setupcolumnset [answers] [distance=2.5em, balance=yes] %\def\startquestions{\exercises{Exercises}\startcolumns[n=2]} %\def\stopquestions{\stopcolumns} \def\startquestions{\exercises{Exercises}\startcolumnset[exercises]} \def\stopquestions{\stopcolumnset} %\def\placeanswers{% % \bgroup % \doifmodeelse{short} % { % \keepblocks[shortsubanswer,longsubanswer] % \answers{Answers}\vskip 1em\startcolumns[n=2] % \selectblocks[shortanswer][criterium=section] % \stopcolumns % } % { % \keepblocks[shortsubanswer,longsubanswer] % \answers{Solutions}\vskip 1em % \selectblocks[longanswer][criterium=section] % } % \egroup %} \def\placeanswers{% \bgroup \doifmodeelse{short} { \keepblocks[shortsubanswer,longsubanswer] \answers{Answers}\vskip 1em\startcolumnset[answers] \selectblocks[shortanswer][criterium=section] \stopcolumnset } { \keepblocks[shortsubanswer,longsubanswer] \answers{Solutions}\vskip 1em \selectblocks[longanswer][criterium=section] } \egroup } We can now no longer compile what we could formerly compile: systems : end file chapter0/equations at line 77 systems : begin file chapter0/equationsexercises at line 79 (../chapter0/equationsexercises.tex system : module newmat (line 31) already loaded system : module math=ext (line 32) already loaded system : module fig-base (line 33) already loaded [24.24] exercises : - Exercises ! Missing number, treated as zero. <to be read again> y \v!yes ->y es \doindecrement ...ned \else \ifx #2\relax \else #2 \fi \fi +#1\relax } \doifelse ... \!!stringa {#1}\edef \!!stringb {#2} \ifx \!!stringa \!! stringb... \doregister ...sterparameter \c!ownnumber }\v!yes {\dosingleempty \dodoregis... \Tindex #1->\index {#1}#1 ... l.104 \setnumber [page]{\pagenumberExercisesOneTwo} If I go into the offending file and comment out the line: \startquestions %\setnumber[page]{\pagenumberExercisesOneTwo} Compiling again: systems : end file chapter0/equations at line 77 systems : begin file chapter0/equationsexercises at line 79 (../chapter0/equationsexercises.tex system : module newmat (line 31) already loaded system : module math=ext (line 32) already loaded system : module fig-base (line 33) already loaded [24.24] exercises : - Exercises ! Missing number, treated as zero. <to be read again> y \v!yes ->y es \doindecrement ...ned \else \ifx #2\relax \else #2 \fi \fi +#1\relax } \doifelse ... \!!stringa {#1}\edef \!!stringb {#2} \ifx \!!stringa \!! stringb... \doregister ...sterparameter \c!ownnumber }\v!yes {\dosingleempty \dodoregis... \Tindex #1->\index {#1}#1 ... l.105 ? We are at a complete loss of what to do.