[XeTeX] Fontspec 1.8 problem?

[Herbert Schulz]

Howdy,

I get a

! LaTeX Error: Command `\colon' already defined.

error with fontspec 1.8 & xunicode 0.5 when compiling the following  
sample file:

%!TEX TS-program = xelatex
%!TEX encoding = UTF-8 Unicode
\documentclass{article}
\usepackage{amsmath}

\usepackage{fontspec}
\usepackage{xunicode}
\defaultfontfeatures{Mapping=tex-text}
\setromanfont[Numbers=Lining,Scale=1.05]{Hoefler Text}

%\usepackage{amsmath}

\begin{document}
%\setromanfont[Numbers=Lining,Scale=1.05]{Hoefler Text}
Here is an Upper Case Gamma: \(\Gamma\)!

Here are some more: \(\{\), \(\}\), \(\land\), \(\lor\),
\(\aleph\), and \(\neg\).

How about a math accent: \(\dot x = \ddot x\).

\end{document}

no matter which \usepackage{amsmath} or \setromanfont{...} version I  
use. I get the same if I try to use Lucida New Math or other errors  
in other orders.

Good Luck,

Herb Schulz
(herbs at wideopenwest.com)