# fontspec related font setting compiles on Linux, but not on Windows

I have this portion of code:

\documentclass{scrartcl}
\usepackage{amsmath, fontspec}
\usepackage[math-style=TeX, bold-style=TeX]{unicode-math}

\setmathfont[StylisticSet=0]{xits-math.otf}
\setmathfont[range={\mathcal,\mathbfcal}, StylisticSet=1]{xits-math.otf}

\begin{document}
$p + q = 1$
$\mathcal{AaBbCcDdEeFfGgHhIiJjKkLlMmNnOoPpQqRrSsTtUuVvWwXxYyZz}$
\end{document}


As you can see, I'm selecting a stylistic set for xits-math.otf. I do this, to get a representation of calligraphic letters in math mode, that conforms to guidelines at my institute.

Now, Because of the line \setmathfont[range={\mathcal,\mathbfcal}, StylisticSet=1]{xits-math.otf} the document doesn't compile on Windows. On Linux, it does compile fine. When the line is commented out, it does compile on Windows as well.

I'm using TeXlive on both systems (Fedora 20 and Windows 7), with pretty much all packages installed, and I made sure, that xits-math.otf is found on both machines (on Windows, the files in question are installed into C:\Windows\Fonts\).

Why?

xelatex version on Linux:

XeTeX 3.1415926-2.6-0.9999.3 (TeX Live 2014/dev)

xelatex version on Windows:

XeTeX 3.14159265-2.6-0.99991 (TeX Live 2014/W32TeX)

-
There's a chance that you have an updated fontspec version in one of these distributions; there is a known error that will be fixed shortly. If this is the case, load the fixltx2e package early to resolve the problem. If not, please add additional information, such as what the error message actually is. –  Will Robertson Jun 28 at 16:11
@WillRobertson: Yes, it is the \dimexpr-error. The document works fine with \RequirePackage{fixltx2e}. –  Ulrike Fischer Jun 28 at 16:27
@UlrikeFischer it does complain about \dimexpr, what should I do, to fix this (as an interim solution)? –  polemon Jun 28 at 18:25
Well as Will and me wrote already: load fixltx2e. –  Ulrike Fischer Jun 28 at 19:34
Erm, OK, I'll try as soon as I get back to that Windows system. Since this is a "well known" bug, any ideas when this will be fixed? –  polemon Jun 28 at 20:38