DOCBOOK: Parsing Problems with DocBook XML DTD V4.1.2

hi,

i'm newbie with DocBook following "the
definitive guide".. now i'm lost in some
trouble at parsing a simple document,
i receive errors like:

jade:/opt/sgml/docbook/4.1.2/docbookx.dtd:74:17:E: "X20AC" is not a 
function name
jade:/opt/sgml/docbook/4.1.2/ent/iso-amsa.ent:8:19:E: "X21B6" is not a 
function name
jade:/opt/sgml/docbook/4.1.2/ent/iso-amsa.ent:9:19:E: "X21B7" is not a 
function name
..

shows some probs with entities but can't
find out where is the problem.. anyone has
a hint? (i'm using jade 1.2.1, SP 1.3.4)

another prob is finding the public "-//James Clark//DTD DSSSL Style 
Sheet//EN"
anyone has a short tip where i/jade can find it? ;)

thanks,
Torben