Don't understand an error message from XSV

I am working with IPC (http://www.ipc.org/) on the development of schema.  
The first project is a set of schemas that define a file format for 
exchanging design information of printed circuit board and printed circuit 
assembly products.  About half of the 20+ schemas have been completed.  

I've found the Primer to be most helpful, but some of the terminology used in 
the "XML Schema Part 1: Structures" has been difficult to interpret.  I am 
currently stumped by an error message from the XSV that has something to do 
with the document root.  A search through Part 1 describes the root document 
in the context of ID and IDREF.  I have no ID or IDREF definitions in my 
document. The documentation is not helping in understanding what is 
considered incorrect in an XML Schema and XML instance file.  

The schemas and the test data file were created Turbo XML. The tools report 
no errors with the current schema.  The instance file is not fully populated. 
About the first half is correct.  Some errors with the auto-generated data 
from the tool are reported later in the document.  The instance file and the 
schema are available at:

   http://webstds.ipc.org/dev/testData.01.xml   
   http://webstds.ipc.org/dev/2511B.01.xsd 

Here is the error message reported by http://www.w3.org/2001/03/webdata/xsv:

  Schema validating with XSV 1.178/1.88 of 2001/03/17 12:11:13

     Target: http://webstds.ipc.org/dev/testData.01.xml 
        (Real name: http://webstds.ipc.org/dev/testData.01.xml
         Length: 3761 bytes 
         Last Modified: Sun, 25 Mar 2001 22:59:00 GMT
         Server: Netscape-Enterprise/4.1) 
     docElt: {http://webstds.ipc.org/dev/2511B.01.xsd}GenCAM 
     No declaration for document root found, validation was lax 
     schemaLocs: 
     schemaDocs: http://webstds.ipc.org/dev/2511B.01.xsd 
     The schema(s) used for schema-validation had no errors 
     No schema-validity problems were found in the target 

  Schema resources involved

  Attempt to import a schema document from   
 http://webstds.ipc.org/dev/2511B.01.xsd for
 http://webstds.ipc.org/dev/2511B.01.xsd, failed

Received on Sunday, 25 March 2001 18:40:16 UTC