ntheorem thref not working in section titles

Question

When I try to refer to a theorem in a section title with thref, I get the error message at the end of this question. Is there a way to fix this?

Latex Error: ./seppathq.tex:57 Argument of \@xtrplargoom has an extra }.

Runaway argument?
{\M@sect {subsection}{2}{\subsecindent }{\beforesubsecskip }{\aftersubsecskip \
Latex Error: ./seppathq.tex:57 Paragraph ended before \@xtrplargoom was complete.
Latex Error: ./seppathq.tex:57 Undefined control sequence.
Latex Error: ./seppathq.tex:57 Missing \endcsname inserted.

Runaway argument?

{{\M@sect {subsection}{2}{\subsecindent }{\beforesubsecskip }{\aftersubsecskip 
Latex Error: ./seppathq.tex:218 TeX capacity exceeded, sorry [main memory size=3000000].
Latex Error: ./seppathq.tex:218 ==> Fatal error occurred, no output PDF file produced!

Answer 1

The following works:

\documentclass{article}
\usepackage[thref]{ntheorem}
\newtheorem{thm}{Theorem}
\begin{document}
\section{Test}
Test
\begin{thm}\label{test}
Test
\end{thm}

\subsection{Proof of \protect\thref{test}}
Test
\end{document}

Remove the .aux file before retrying: the preceding run without \protect has surely corrupted it.