bzr ubuntu:hello failed

cc11rocks@cc11rocks:~/hello$ bzr bd -- -S
Building using working tree
Building package in normal mode
Purging the build dir: /home/cc11rocks/build-area/hello-2.8
Looking for a way to retrieve the upstream tarball
Upstream tarball already exists in build directory, using that
Building the package in /home/cc11rocks/build-area/hello-2.8, using debuild -S
 dpkg-buildpackage -rfakeroot -d -us -uc -S
dpkg-buildpackage: export CFLAGS from dpkg-buildflags (origin: vendor): -g -O2 -fstack-protector --param=ssp-buffer-size=4 -Wformat -Wformat-security
dpkg-buildpackage: export CPPFLAGS from dpkg-buildflags (origin: vendor): -D_FORTIFY_SOURCE=2
dpkg-buildpackage: export CXXFLAGS from dpkg-buildflags (origin: vendor): -g -O2 -fstack-protector --param=ssp-buffer-size=4 -Wformat -Wformat-security
dpkg-buildpackage: export FFLAGS from dpkg-buildflags (origin: vendor): -g -O2
dpkg-buildpackage: export LDFLAGS from dpkg-buildflags (origin: vendor): -Wl,-Bsymbolic-functions -Wl,-z,relro
dpkg-buildpackage: source package hello
dpkg-buildpackage: source version 2.8-2
dpkg-buildpackage: source changed by Santiago Vila <sanvila@debian.org>
 dpkg-source --before-build hello-2.8
 fakeroot debian/rules clean
rm -f build
[ ! -f Makefile ] || /usr/bin/make distclean
rm -rf *~ debian/tmp debian/*~ debian/files* debian/substvars
 dpkg-source -b hello-2.8
dpkg-source: info: using source format `3.0 (quilt)'
dpkg-source: info: building hello using existing ./hello_2.8.orig.tar.gz
dpkg-source: info: building hello in hello_2.8-2.debian.tar.gz
dpkg-source: info: building hello in hello_2.8-2.dsc
 dpkg-genchanges -S >../hello_2.8-2_source.changes
dpkg-genchanges: not including original source code in upload
 dpkg-source --after-build hello-2.8
dpkg-buildpackage: binary and diff upload (original source NOT included)
Now running lintian...
W: hello source: out-of-date-standards-version 3.9.2 (current is 3.9.3)
Finished running lintian.
Now signing changes and any dsc files...
 signfile hello_2.8-2.dsc Santiago Vila <sanvila@debian.org>
gpg: skipped "Santiago Vila <sanvila@debian.org>": secret key not available
gpg: /tmp/debsign.w7cPWijV/hello_2.8-2.dsc: clearsign failed: secret key not available
debsign: gpg error occurred!  Aborting....
debuild: fatal error at line 1271:
running debsign failed
bzr: ERROR: The build failed.