Issue on pdf(La)TeX with named colors in dvipsnames

Issue on pdf(La)TeX with named colors in dvipsnames

When compiled on pdfLaTeX, the following code (and MWE) returns a
PostScript error message:
\documentclass{article}
\usepackage[dvipsnames]{xcolor}
\usepackage{pstricks}
\usepackage[pdfcrop={--hires}]{auto-pst-pdf}
\begin{document}
\begin{pspicture}(0,0)(1,1)
\psframe*[linecolor=Maroon](0,0)(1,1)
\end{pspicture}
\end{document}
The error message reads:
/undefined in Maroon
and no graphic is generated.
This is related to the dvipsnames option and pdfLaTeX, because on the one
hand it works fine on XeLaTeX as it is and, on the other, it works fine on
pdfLaTeX if I set svgnames (which defines a Maroon color name) as option
for the xcolor package.
I have the definitions file dvipsnam.def, and a complete MikTeX 2.9
installation running on Windows Xp. I have reinstalled already the xcolor
package. The issue started all of a sudden after an automated Windows
update, but I cannot state that this is the reason behind it. Furthermore,
it's the only issue I've detected. Somebody out there has any suggestions?