I tried to compile the file README.tex in DocbookInConteXt and obtain the following message :
undefined control sequence : stelsectiein
Here are the instructions in xtag-docbook.tex my installation of ConteXt does not understand
Delete those lines or create the "nl" interface. These lines don't belong there.
Well, if you are a programmer, you might think of cleaning up the module and publish an updated version, it has been orphaned for quite some time now and ConTeXt developed further meanwhile.