What am I doing wrong??

Hi,

I have a schema and a XML file that I want to validate against the schema. But when I try to do this, I get an error message:

[Error] teste.xml:2:15: Attribute "xmlns" must be declared for element type "artigo".

[Error] teste.xml:3:24: Attribute "ultima_revisao" must be declared for element type "artigo".

[Error] teste.xml:4:16: Attribute "versao" must be declared for element type "artigo".

java.lang.ArrayIndexOutOfBoundsException: -1

I'm using xerces DOMParser, and my files are can be found at:

www.inf.ufrgs.br/~vanessa/XML/teste.xsd

www.inf.ufrgs.br/~vanessa/XML/teste.xml

So, my questions are: Is my namespace declaration wrong?? Is the Namespace declaration mandatory for any document??

Thanks in advance

Vanessa