The catalog file contains references for Docbook 4.3, have you changed the docbook version number in documentation files perhaps? If yes then this could be the reason why the build system tries to download XSL stylesheets from the internet.
Checking modules directory I see that we have both 4.2 and 4.4 used. Maybe we should standardize and make sure that we have the 4.4 files referenced.
/O
agave:modules olle$ grep 'OASIS//DTD' */doc/*.xml auth_identity/doc/auth_identity.xml:<!DOCTYPE section PUBLIC "-// OASIS//DTD DocBook XML V4.2//EN" auth_radius/doc/auth_radius.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" auth_radius/doc/auth_radius_admin.xml:<!DOCTYPE book PUBLIC "-//OASIS// DTD DocBook XML V4.4//EN" avpops/doc/avpops.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" avpops/doc/avpops_admin.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" carrierroute/doc/carrierroute.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" carrierroute/doc/carrierroute_admin.xml:<!DOCTYPE book PUBLIC "-// OASIS//DTD DocBook XML V4.4//EN" carrierroute/doc/carrierroute_db.xml:<!DOCTYPE book PUBLIC "-//OASIS// DTD DocBook XML V4.4//EN" cfg_db/doc/cfg_db.xml:<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" cfg_rpc/doc/cfg_rpc.xml:<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" cfg_rpc/doc/rpc.xml:<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" ctl/doc/ctl.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4// EN" ctl/doc/params.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" ctl/doc/rpc.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4// EN" db_berkeley/doc/db_berkeley.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" db_berkeley/doc/db_berkeley_admin.xml:<!DOCTYPE book PUBLIC "-//OASIS// DTD DocBook XML V4.4//EN" db_flatstore/doc/flatstore.xml:<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" db_flatstore/doc/functions.xml:<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" db_flatstore/doc/params.xml:<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" dialplan/doc/dialplan.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" dialplan/doc/dialplan_admin.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" dialplan/doc/dialplan_devel.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" enum/doc/enum.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" enum/doc/enum_admin.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" iptrtpproxy/doc/iptrtpproxy.xml:<!DOCTYPE section PUBLIC "-//OASIS// DTD DocBook XML V4.2//EN" lcr/doc/lcr.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4// EN" lcr/doc/lcr_admin.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" mediaproxy/doc/mediaproxy.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" mediaproxy/doc/mediaproxy_admin.xml:<!DOCTYPE book PUBLIC "-//OASIS// DTD DocBook XML V4.4//EN" mi_rpc/doc/mi_rpc.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" mi_rpc/doc/mi_rpc_admin.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" misc_radius/doc/misc_radius.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" misc_radius/doc/misc_radius_admin.xml:<!DOCTYPE book PUBLIC "-//OASIS// DTD DocBook XML V4.4//EN" pdb/doc/pdb.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4// EN" pdb/doc/pdb_admin.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" peering/doc/peering.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" peering/doc/peering_admin.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" tls/doc/certs_howto.xml:<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" tls/doc/functions.xml:<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" tls/doc/history.xml:<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" tls/doc/params.xml:<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" tls/doc/tls.xml:<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" tm/doc/api.xml:<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" tm/doc/functions.xml:<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" tm/doc/params.xml:<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" tm/doc/tm.xml:<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" topoh/doc/topoh.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" topoh/doc/topoh_admin.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" utils/doc/utils.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" utils/doc/utils_admin.xml:<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN" xmlrpc/doc/functions.xml:<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" xmlrpc/doc/params.xml:<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" xmlrpc/doc/xmlrpc.xml:<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"