Error loading file

["David R. Patterson" <patterd1 comcast net>]

I'm using Dia 0.91 on Windows.  I've created a file in XML that seems to 
be just like the format of other Dia files I've saved and browsed.  When 
I do a "File->Open" on it, I get an error "Not a Dia file".  Is there a 
way to get more information about this?  I've checked the file against 
the DTD and it validates OK. 

Can anyone give me a hint as to what causes this error?

Thanks.

David Patterson
patterd1 at comcast dot net
working on a tool to drive data into Dia