il log dice:

for templ in ; do \
cp $templ `echo $templ | sed -e ’s/_KVERS_/2.6.29-1-686/g’` ; \
done
for templ in `ls debian/*.modules.in` ; do \
test -e ${templ%.modules.in}.backup || cp ${templ%.modules.in} ${templ%.modules.in}.backup 2>/dev/null || true; \
sed -e ’s/##KVERS##/2.6.29-1-686/g ;s/#KVERS#/2.6.29-1-686/g ; s/_KVERS_/2.6.29-1-686/g ; s/##KDREV##/2.6.29-1/g ; s/#KDREV#/2.6.29-1/g ; s/_KDREV_/2.6.29-1/g ‘ ${templ%.modules.in}; \
done
dh_testroot
dh_clean -k
# Build the module
kmk -C /lib/modules/2.6.29-1-686/build M=/usr/src/modules/virtualbox-ose
kmk[1]: Entering directory `/usr/src/linux-headers-2.6.29-1-686′
kmk[2]: Entering directory `/usr/src/linux-headers-2.6.29-1-common’
kmk[3]: Entering directory `/usr/src/linux-headers-2.6.29-1-686′
/usr/src/linux-headers-2.6.29-1-common/arch/x86/Makefile:41: /usr/src/linux-headers-2.6.29-1-common/arch/x86/Makefile_32.cpu: No such file or directory
kmk[3]: *** No rule to make target `/usr/src/linux-headers-2.6.29-1-common/arch/x86/Makefile_32.cpu’. Stop.
kmk[3]: Leaving directory `/usr/src/linux-headers-2.6.29-1-686′
kmk[2]: *** [sub-make] Error 2
kmk[2]: Leaving directory `/usr/src/linux-headers-2.6.29-1-common’
kmk[1]: *** [all] Error 2
kmk[1]: Leaving directory `/usr/src/linux-headers-2.6.29-1-686′
kmk: *** [binary-modules] Error 2
make: *** [kdist_build] Error 2
kmk -f debian/rules clean
kmk: Nothing to be done for `clean’.
kmk -f debian/rules kdist_clean kdist_config binary-modules
kmk -f debian/rules clean
kmk[1]: Entering directory `/usr/src/modules/virtualbox-ose’
kmk[1]: Nothing to be done for `clean’.
kmk[1]: Leaving directory `/usr/src/modules/virtualbox-ose’
kmk: Nothing to be done for `kdist_config’.

Qualche idea?