[XeTeX] fancyhdr and gb4e clash

[Sven Siegmund]

Hello,

I use XeTeX 3.1415926-2.2-0.999.2 (MiKTeX 2.7) on Win XP SP2 and I
have tried to spice up the layout of a document with the fancyhdr
package. Unfortunately I get a strange error the exact cause of which
is obscure to me.

Having reduced my document to the minimal example I have this:

\documentclass[a4paper,12pt,twoside]{article}

\usepackage{xltxtra} % loads also xunicode, fontspec, graphicx
\usepackage{gb4e} % for linguistic glosses
\usepackage{fancyhdr} % better style
\pagestyle{fancy}

\begin{document}
something
\end{document}

I get this error when compiling:
...
(C:\MiKTeX\tex\latex\gb4e\gb4e.sty (C:\MiKTeX\tex\latex\gb4e\cgloss4e.sty))
(C:\MiKTeX\tex\latex\fancyhdr\fancyhdr.sty) (clash.aux)
! Argument of ^ has an extra }.
<inserted text>
                \par
l.15 \end{document}

?

However, the minimal example compiles well if I don't load the gb4e
package. The problem is, I must load it. I have to use it for
linguistic glosses. Is there a solution?

Thanks,

S.