XML help needed

[Duncan Smith]

I have a lot of code written for a particular application I'm working on and
I've got to the point where I need to access data from XML files.  I will
also need to save to XML files.  There's almost too much information
available and I'd appreciate any advice.  SAX?  DOM?  Some nice easy
examples?

I have the proposed DTD and examples of supposedly valid XML files.  The XML
files are apparently well-formed, but (according to XML Spy) not valid.
'Invalid value for datatype NMTOKENS in attribute INDEXES'.  I think the
following are the relevant lines from the DTD and XML respectively.  Can
anyone tell me what's wrong?  Thanks in advance.

<?xml version="1.0" encoding="ISO-8859-1"?>

<!ATTLIST DPI INDEXES NMTOKENS #IMPLIED>



<?xml version="1.0"?>

<DPI INDEXES=" 0 0 "> 1 0 0</DPI>