There is something wrong with LaTeX output of some textclasses. I can reproduce this, for example, with beamer, when trying to view the file beamerpresentation that is shipped with the beamer package (in the "templates" directory).
It turned out that LyX is erroneously outputting commands as _environments_. Consider the following diff between the LaTeX output of 1.3 and 1.4: +\begin{title} +Presentation Title -\title[Short Title (Optional)]{Presentation Title} - - -\author[Short Author Name (Optional)]{Author Name\inst{1} \and Another Author\inst{2}} - - -\date[Short Date (Optional)]{Date} - - -\institute[Short Institute (Optional)]{\inst{1}Institute\and \inst{2}Another Institute} +\end{title} +\begin{author} +Author Name\inst{1} \and Another Author\inst{2} + +\end{author} +\begin{date} +Date + +\end{date} +\begin{institute} whereas, for instance, title is defined in beamer.layout as # Title style definition Style Title Margin Static LatexType Command InTitle 1 LatexName title ParSkip 0.4 ItemSep 0 TopSep 0 BottomSep 1 ParSep 1 Align Center AlignPossible Center LabelType No_Label OptionalArgs 1 # standard font definition Font Size Huge Series Bold Color Blue EndFont End I guess we should have a look at this before 1.4 Jürgen