I have two files in same directory: XML and DTD.
When I try to validate XML, NPP shows me an error message:
How to use local DTD files?
The loading process for external DTD should work. This message occures when
a) the DTD file is unreachable
b) the parser cannot load the DTD due to invalid structure.
I've tested the plugin with XML and DTD available on http://www.idevelopment.info/data/Programming/java/xml/ExampleXMLandDTDFile.html and it's working fine.