Guile 2.0.11 error during test of package definition on Trisquel 7

[swedebugia]

Hi

I tried following the manual build* from a fresh git pull.

From 7.6:
"   ./pre-inst-env guix build gnew --keep-failed
   If the package is unknown to the ‘guix’ command, it may be that the
source file contains a syntax error, or lacks a ‘define-public’ clause
to export the package variable.  To figure it out, you may load the
module from Guile to get more information about the actual error:

     ./pre-inst-env guile -c '(use-modules (gnu packages gnew))'"

After putting the new package definition below into python.scm:
(define-public python-twisted
  (package
    (name "python-twisted")
    (version "15.5.0")
    (source
     (origin
       (method url-fetch)
;       (extension "tar.bz2")
;       (uri (pypi-uri "Twisted" version extension))
       (uri (pypi-uri "Twisted" version))
       (sha256
        (base32
         "0zy18lcrris4aaslil5k12i13k56c32hzfdv6h10kbnzl026h158"))))
    (build-system python-build-system)
    (inputs
     `(("python-setuptools" ,python-setuptools)))
    (home-page "http://twistedmatrix.com/";)
    (synopsis
     "An asynchronous networking framework written in Python")
    (description
     "An asynchronous networking framework written in Python")
    (license license:expat)))

./pre-inst-env guix build cannot find it.
I then do:
$ ./pre-inst-env guile -c '(use-modules (gnu packages python))'
but it tries to auto-compile python.scm and fails with:
;;; ERROR: failed to create path for auto-compiled file "path/to/file"

WTF?

From within guix environment guix --container:
it compiles without errors.

cheers
swedebugia