Wiki not allowing file uploads or replacements

[heazels]

The wiki does not appear to be allowing new files to be uploaded or existing files to be replaced?

[heazels]

example error message

Could not open lock file for "mwstore://local-backend/local-public/archive".
Could not open lock file for "mwstore://local-backend/local-public/archive/20131204063615!Quillmane2.png".