Reference to non-SGML character Error Message

In HTML files with the following DTD
certain character entities are flagged as errors. Please see the example

 ... lass="bold">*M/S/C Creighton/O&#146;Keefe Moved to go into E ...
     Error: reference to non-SGML character 

I'm not exactly sure why that is technically invalid but I am not aware of
any browsers that have a problem with it. The problem also happens with
character entities &#148; &#150;

Also, I tried it with another DTD validator and it did not report a problem.

Richard T. Kennedy
The Boeing Company
PO Box 3999  MC 8R-03
Seattle, WA  98124-2499

Received on Friday, 28 June 2002 14:59:58 UTC