strange semodule_expand error during linking

[Mr Dash Four]

I am trying to build a cut-down version of the targeted policy where I 
have turned quite a few modules in modules-targeted.conf to "off" 
instead of "module" (i.e. no compilation and inclusion in the final 
version of the policy). Compilation and linking goes well, though during 
the final stage I am getting the following error:

/usr/bin/semodule_expand tmp/test.lnk tmp/policy.bin
libsepol.sepol_module_package_read: invalid module in module package (at 
section 0)
/usr/bin/semodule_expand:  Error in reading package from tmp/test.lnk
make: *** [validate] Error 1
error: Bad exit status from /var/tmp/rpm-tmp.3z0Tfc (%install)

I am using the latest policy for FC15. Any ideas what could be the cause 
for this?