When you say "non-namespaced" does that mean you have added via a DOM level 1 call, or simply that the XML looks something like :
<myns:elt1 attributewithoutns="a test"/>
The latter should work. I haven't tried it myself, but my understanding is the former is likely to fail (use L2 calls instead, with a null NS - e.g. setAttributeNS).
My understanding is exactly the same Berin ;-) I have seen NullPointerExceptions with DOM L1 calls on numerous occassions.
Erwin