RE: p:data and error codes

> Do we want to say 
> anything about which
> schemes are supported? I think not.

If p:load demands that 'file' and 'http' must be supported, I would say
that the same should apply also for p:document and p:data. Perhaps we
could make a general note somewhere in the spec saying that anywhere
where content can be read from a URI, 'file' and 'http' must be
supported. Or we could drop the requirement for 'file' and 'http'
schemes altogether.

Regards,
Vojtech