[SENR0001] Attributes cannot be serialized:db:open-pre("docdb",7).
This is in compliance with the spec, which prevents attributes from being serialized without their elements. A simple example that triggers the error:
<a b="c"/>/@b
This is how you can request the attribute value:
<a b="c"/>/@b/data()
This is how you can request its name:
<a b="c"/>/@b/name()