I implemented some time ago an option called "load-external-dtd" that you can use to tell the parser not to even try to load the DTD. The actual name is: http://apache.org/xml/features/nonvalidating/load-external-dtd
In case you wonder, when this is on (the default) xerces tries to read the DTD even though you turned validation off because it tries to get things like entities, and default attributes. -- Arnaud Le Hors - IBM Cupertino, XML Strategy Group
