Unable to use DocBook PNG Variant

[Liam Hazell <liamh dragon net au>]

Hi all,

I'm still having difficulties using the DocBook PNG Variant DTD (the
standard DocBook 3.1 DTD works fine). My SGML document begins:

<!DOCTYPE Article PUBLIC "-//GNOME//DTD DocBook PNG Variant V1.0//EN" [

When I try to validate, I receive the following error message:

nsgmls:color_picker.sgml:1:70:W: cannot generate system identifier for
public text "-//GNOME//DTD DocBook PNG Variant V1.0//EN"

png-support-3.1.dtd is located in both /usr/share/sgml/gnome/ and
/usr/lib/sgml/. docbook.dtd is located in /usr/lib/sgml/.

The last lines in /usr/lib/sgml/CATALOG are:

PUBLIC  "-//GNOME//DTD DocBook PNG Variant V1.0//EN"
	"png-support-3.1.dtd"
CATALOG "/var/lib/sgml/CATALOG.docbk31"
CATALOG "/var/lib/sgml/CATALOG.docbk30"

Any suggestions as to what needs to be done to resolve this issue would
be greatly appreciated. Thanks.


Liam.