Problems with Debian finding modules

I'm trying to roll my own TMDA .debs, and am running into this:

    Traceback (most recent call last):
      File "/usr/bin/tmda-sendmail", line 40, in ?
	from TMDA import Version
    ImportError: No module named TMDA

I'm not sure what that's really telling me, since there's no module
named TMDA in the tarball as far as I can see anyway.

Here's my debian/rules file:

    #!/usr/bin/make -f
    #
    # Uncomment this to turn on verbose mode.
    #export DH_VERBOSE=1

    build:

    clean:
	    dh_testdir
	    dh_testroot
	    dh_clean
	    find . -name '*.pyc' -exec rm -f "{}" \;

    install: build
	    dh_testdir
	    dh_testroot
	    dh_clean -k
	    dh_installdirs

	    cp -a bin/tmda-* debian/tmda/usr/bin
	    cp -a templates/* debian/tmda/etc/tmda
	    cp -a TMDA/* debian/tmda/usr/lib/tmda/

    binary-indep: build install
	    dh_testdir
	    dh_testroot
	    dh_installchangelogs
	    dh_installdocs
	    dh_link
	    dh_compress
	    dh_fixperms
	    dh_python
	    dh_installdeb
	    dh_gencontrol
	    dh_md5sums
	    dh_builddeb

    binary: binary-indep

    binary-arch: build install

    binary: binary-indep binary-arch
    .PHONY: build clean binary-indep binary-arch binary install

So where am I going wrong here? My understanding is that dh_python
should be registering the modules with the system automagically, but
perhaps not.

Also, AFAICT the debian-python policy says that byte-compiled files
shouldn't be in .deb packages and that dh_python will strip out the pyc
files anyway. Could part of the problem be that compileall isn't being
run as a post-install routine?

-- 
Unabashedly littering the information superhighway with detritus like
this for over 15 years now.