After enabling debug, it threw loads of messages. Attached error.log.

Excerpt from the error.log

[Tue Mar 12 03:28:02 2013] [error]   File "/usr/lib/python2.7/dist-packages/compressor/templatetags/compress.py", line 81, in render
[Tue Mar 12 03:28:02 2013] [error]     cached_offline = self.render_offline(compressor, forced)
[Tue Mar 12 03:28:02 2013] [error]   File "/usr/lib/python2.7/dist-packages/compressor/templatetags/compress.py", line 56, in render_offline
[Tue Mar 12 03:28:02 2013] [error]     raise OfflineGenerationError('You have offline compression enabled but key "%s" is missing from offline manifest. You may need to run "python manage.py compress".' % key)
[Tue Mar 12 03:28:02 2013] [error] OfflineGenerationError: You have offline compression enabled but key "8d04d8326e2e8769c59d083ce0bb9657" is missing from offline manifest. You may need to run "python manage.py compress".


Executing python manage.py, compress.py and compress.pyc results as below.

root@grizzly:/var/log/apache2# cd /usr/lib/python2.7/dist-packages/compressor/templatetags/
root@grizzly:/usr/lib/python2.7/dist-packages/compressor/templatetags# python manage.py compress
python: can't open file 'manage.py': [Errno 2] No such file or directory
root@grizzly:/usr/lib/python2.7/dist-packages/compressor/templatetags# ls
compress.py  compress.pyc  __init__.py  __init__.pyc
root@grizzly:/usr/lib/python2.7/dist-packages/compressor/templatetags# python compress.py compress
Traceback (most recent call last):
  File "compress.py", line 4, in <module>
    from compressor.cache import (cache_get, cache_set, get_offline_hexdigest,
  File "/usr/lib/python2.7/dist-packages/compressor/cache.py", line 5, in <module>
    from django.core.cache import get_cache
  File "/usr/lib/python2.7/dist-packages/django/core/cache/__init__.py", line 76, in <module>
    if not settings.CACHES:
  File "/usr/lib/python2.7/dist-packages/django/utils/functional.py", line 184, in inner
    self._setup()
  File "/usr/lib/python2.7/dist-packages/django/conf/__init__.py", line 40, in _setup
    raise ImportError("Settings cannot be imported, because environment variable %s is undefined." % ENVIRONMENT_VARIABLE)
ImportError: Settings cannot be imported, because environment variable DJANGO_SETTINGS_MODULE is undefined.
root@grizzly:/usr/lib/python2.7/dist-packages/compressor/templatetags# python compress.pyc compress
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/compressor/templatetags/compress.py", line 4, in <module>
    from compressor.cache import (cache_get, cache_set, get_offline_hexdigest,
  File "/usr/lib/python2.7/dist-packages/compressor/cache.py", line 5, in <module>
    from django.core.cache import get_cache
  File "/usr/lib/python2.7/dist-packages/django/core/cache/__init__.py", line 76, in <module>
    if not settings.CACHES:
  File "/usr/lib/python2.7/dist-packages/django/utils/functional.py", line 184, in inner
    self._setup()
  File "/usr/lib/python2.7/dist-packages/django/conf/__init__.py", line 40, in _setup
    raise ImportError("Settings cannot be imported, because environment variable %s is undefined." % ENVIRONMENT_VARIABLE)
ImportError: Settings cannot be imported, because environment variable DJANGO_SETTINGS_MODULE is undefined.
root@grizzly:/usr/lib/python2.7/dist-packages/compressor/templatetags#