LyX: Undefined control sequence \hline

Question

Running LyX on Windows 7 with MiKTeX. I was trying to export LyX's "Embedded Objects tutorial" to PDF, but got this error:

Undefined control sequence

\hline

The control sequence at the end of the top line
of your error message was never \def'ed. If you have
misspelled it (e.g., `\hobx'), type `I' and the correct
spelling (e.g., `I\hbox'). Otherwise just continue,
and I'll forget about whatever was undefined.

The offending code seems to be

\let\myHlineC\hline
\renewcommand{\hline}
 {\arrayrulecolor{red}\myHlineC\arrayrulecolor{black}}

(section 2.11.2 of the document).

May or may not be relevant: The document's preamble.

Answer 1

You can download the pdf of the manual online here: http://wiki.lyx.org/LyX/DocumentationDevelopment#EmbeddedObjects

Do you have the following packages installed? arydshln, colortbl, diagbox, lettrine, marginnote, picinpar and sidecap

Although it says that you should be able to export without them, I've found that sometimes they are required. If this is true in your case, can you post which package was causing the problem so we can try to fix the document? To find this out, install the above packages one by one and test if you can export after each one. Don't forget to reconfigure LyX via Tools > Reconfigure after each install of a new package.