bf build failing, aparantly due to missing file

[ferret@phonewave.net]

make[1]: Entering directory
`/share/acct/idalton/work-in-progress/boot-floppies/documentation'
rm -f messages.ent
ln -s messages_C.ent messages.ent
rm -f dynamic.ent
ln -s dynamic_C_i386.ent dynamic.ent
Verifying SGML validity for Installation Manual, language C:
nsgmls -ges -wall /usr/lib/sgml/declaration/debiandoc.decl install.sgml
nsgmls:E: cannot open "/usr/lib/sgml/declaration/debiandoc.decl" (No such
file or directory)
nsgmls:install.sgml:36:0:E: cannot find "dtd/debiandoc.dtd"; tried
"/usr/lib/sgml/dtd/debiandoc.dtd",
"/usr/local/share/sgml/dtd/debiandoc.dtd",
"/usr/local/lib/sgml/dtd/debiandoc.dtd", "/usr/lib/sgml/dtd/debiandoc.dtd"

I grepped in Contents-i386 for "/usr/lib/sgml/declaration/debiandoc.decl"
and found nil.

I'm wondering what I need to do with my system to get a working build
environment again.

I do have task-debian-devel and suggests installed.