Jing "conflicting ID-types"

Hi James,

Finally got back to working on the XML Encryption rng and made quite a bit 
of progress -- particularly since I got jing and relame working! However, 
while I can validate find under relame, jing is giving me the following 
error for the attached rng. What does this mean?

Error at URL 
"file:/home/reagle/data/2web/WWW/Encryption/2001/Drafts/xmlenc-core/1.rng", 
line number 39: conflicting ID-types for attribute "Id" of element 
"EncryptedKey" from namespace "http://www.w3.org/2001/04/xmlenc#"