I've posted this here and in the comp.lang.java.programmer group
because I'm not really sure if it's a Java problem or an XML problem!

Basically I have written a Java application which loads an XML file and
validates it (it is going to do other stuff with it as well once I get
this validation problem sorted!). I am using JDOM and Xerces-J 2.7.1.
It starts to validate fine but then reports a whole load of errors
which I obtained the details of using Java. The first few look like
this:

WARNING: schema_reference.4: Failed to read schema document
'http://schemas.opengis.net/gml/3.1.1/base/feature.xsd', because 1)
could not find the document; 2) the document could not be read; 3) the
root element of the document is not <xsd:schema>. at line 16, column
121 in entity
http://www.dur.ac.uk/s.j.marjoribanks/geotechml/rawData.xsd

WARNING: schema_reference.4: Failed to read schema document
'http://schemas.opengis.net/gml/3.1.1/base/feature.xsd', because 1)
could not find the document; 2) the document could not be read; 3) the
root element of the document is not <xsd:schema>. at line 10, column
121 in entity http://www.dur.ac.uk/s.j.marjoribanks/agsml/agsml.xsd

WARNING: schema_reference.4: Failed to read schema document
'http://schemas.opengis.net/gml/3.1.1/base/feature.xsd', because 1)
could not find the document; 2) the document could not be read; 3) the
root element of the document is not <xsd:schema>. at line 9, column 121
in entity
http://www.dur.ac.uk/s.j.marjoribanks/agsml/holeInformation.xsd

WARNING: schema_reference.4: Failed to read schema document
'AgsmlBase.xsd', because 1) could not find the document; 2) the
document could not be read; 3) the root element of the document is not
<xsd:schema>. at line 10, column 43 in entity
http://www.dur.ac.uk/s.j.marjoribanks/agsml/holeInformation.xsd

WARNING: schema_reference.4: Failed to read schema document
'http://schemas.opengis.net/gml/3.1.1/base/feature.xsd', because 1)
could not find the document; 2) the document could not be read; 3) the
root element of the document is not <xsd:schema>. at line 9, column 121
in entity
http://www.dur.ac.uk/s.j.marjoribanks/agsml/laboratoryTesting.xsd


The first few errors are all like that, reporting that it could not
access a schema file and then there are loads which i think are
probably as a result of the schema file being inaccessible.
My schema imports quite a few other schemas, but there only seems to be
a problem loading 3 of them. The AgsmlBase.xsd one which is in the same
directory as the target schema of my instance document, the
http://www.schemas.opengis.net/gml/3.1.1/base/feature.xsd schema and an
XLinks one as well (not shown in the errors above). I don't understand
why it is not able to access them though? If I validate my file in
XMLSpy2006 it is ok (apart from one nasty bug which the Altova support
team inform me is a problem with the software). I have checked the URLs
and the schemas are definitley there and I can access them so why can't
it access them?

One though I did have was that if one of them is already imported into
one of the schemas which I import, could this cause a problem? It
doesn't in XMLSpy though and I don't think it should really?

Thanks

Steve