# Undefined control sequence. \pgfplots@already@computed@legend@node [closed]

I got following error in my computer only.

Undefined control sequence.
{des}}};\\\pgfplots@show@... l.261 \end{axis}  here is the code \begin{tikzpicture} \begin{axis}[% width=\figurewidth, height=\figureheight, scale only axis, xmin=0, xmax=20, xlabel={Time (s)}, ymin=-10, ymax=10, ylabel={Angle (deg)}, name=plot2, title={(b)}, legend style={draw=black,fill=white,legend cell align=left} ] \addplot [ color=red, solid, line width=1.0pt ] table{ 0 -5 . . 20 -5 }; \addlegendentry{\theta{}_{\text{des}}\$};

Welcome to TeX.sx! Please add a minimal working example (MWE) that illustrates your problem. It will be much easier for us to reproduce your situation and find out what the issue is when we see compilable code, starting with \documentclass{...} and ending with \end{document}. What is your preamble? Which packages do you load? In which order? By the way, you can use Ctrl+K or the { } button to format code as a code block. Using  works for inline code. –  Qrrbrbirlbel Mar 31 '13 at 0:59
The undefined command is the last one on the first line of the message which is \text that is defined in the amsmath (and amstext`) package. –  David Carlisle Mar 31 '13 at 1:03