Parameter entity error in MathML/XHTML DTD?

When I try to display the web page 
http://www.oxnardcc.org/~mbowen/answers/sf5ch01test1.htm in Windows 98SE 
IE6 with MathPlayer, I get the following error message:

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The XML page cannot be displayed

Cannot view XML input using XSL style sheet. Please correct the error and 
then click the Refresh button, or try again later.

Parameter entity must be defined before it is used. Error processing 
resource 'http://www.w3.org/TR/MathML2/dtd/xhtml-math11-f.dtd'. Line 148, 
Position 2

%xhtml-prefw-redecl.mod;
-^

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Is it the style sheet or is it my coding?

Also, there is a minor error (anti-spam defense?) in the email link at the 
bottom of the page whose URI is http://www.w3.org/Math/XSL/. The "@" has 
been replaced with a ".".

Received on Monday, 1 April 2002 00:55:31 UTC