Oops, I forgot to add the str().
The error mentioned above no longer occurs but I get the original problem back:
```
Traceback (most recent call last):
  File "./buildout/bin/generate_controller", line 20, in <module>
    tilecloud_chain.controller.main()
  File "/home/alex/geoportal/buildout/eggs/tilecloud_chain-0.7.1-py2.7.egg/tilecloud_chain/controller.py", line 85, in main
    _generate_wmts_capabilities(gene)
  File "/home/alex/geoportal/buildout/eggs/tilecloud_chain-0.7.1-py2.7.egg/tilecloud_chain/controller.py", line 209, in _generate_wmts_capabilities
    _send(capabilities, cache['wmtscapabilities_file'], 'application/xml', cache)
  File "/home/alex/geoportal/buildout/eggs/tilecloud_chain-0.7.1-py2.7.egg/tilecloud_chain/controller.py", line 104, in _send
    s3key.put()
  File "/home/alex/geoportal/buildout/eggs/tilecloud-0.2dev_20131025-py2.7.egg/tilecloud/lib/s3.py", line 128, in put
    return self.bucket.put(self.name, self.headers, self.body)
  File "/home/alex/geoportal/buildout/eggs/tilecloud-0.2dev_20131025-py2.7.egg/tilecloud/lib/s3.py", line 188, in put
    return self.connection.put(self.name, '/' + key_name, headers, body)
  File "/home/alex/geoportal/buildout/eggs/tilecloud-0.2dev_20131025-py2.7.egg/tilecloud/lib/s3.py", line 285, in put
    return self.request('PUT', bucket_name, url, body=body, headers=headers)
  File "/home/alex/geoportal/buildout/eggs/tilecloud-0.2dev_20131025-py2.7.egg/tilecloud/lib/s3.py", line 305, in request
    raise S3Error(method, url, body, headers, response)
tilecloud.lib.s3.S3Error: InvalidAccessKeyId: The AWS Access Key Id you provided does not exist in our records.
```