[XeTeX] Scheherazade not rendering properly with XeTeX

[Adam Baker]

Hello,

I am having trouble with a simple XeTeX document. When I run XeTeX
with the input below, I get a fine-looking line of connected Arabic.
If I change the commented line to select Scheherezade instead of
Lateef, the output I get includes a bunch of unconnected Arabic
letters, spaced closely together, with many glyphs different from my
(nonsensical) input. This is on Windows Vista, with both Scheherezade
and Lateef copied directly from their zip files into C:\Windows\Fonts

Any help appreciated. Thanks,
Adam

% begin file
%\font\sch="Scheherazade:script=arab" at 20pt
\font\sch="Lateef:script=arab" at 20pt
\sch
ربیبلیبلیبل
\vfill\eject\bye
% end file
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