[Insight-users] Build InsightDocuments/TheoryBook failed

[xgl99 at mails.tsinghua.edu.cn]

I am using Debian and tetex is 2.0.2
latex output is like this:
---------------------------------------
! LaTeX Error: Not in outer par mode.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.
 ...

l.1506

? X
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the relavant tex code is:
\begin{figure}
\center                   %ERROR HERE!!!
\begin{tabular}[htb]{cccc}
\includegraphics[width=8cm]{HumanLungImage3.eps} &
\includegraphics[width=8cm]{HumanLungImage4.eps} \\
(a) & (b) \\
\includegraphics[width=8cm]{HumanLungField34.eps} &
\includegraphics[width=8cm]{HumanLungStrains34.eps} \\
(c) & (d) \\
\end{tabular}
\caption[Quantifying human lung motion with FEM-based registration]{(a), (b) Two
sequential sagittal slices of the right lung of a healthy male during expiration.
(c) The computed deformation of the image in (a) to the image in (b).  (d) The
strain map corresponding to the deformation field in (c).}
\label{fig:HumanLungMotion}
\end{figure}

What is the problem?