Firefox doesn't use CSS for twenty eleven

Firefox isn’t using the css for the twenty eleven theme. I am using the WP network function. The blogs using the twenty ten theme are fine in every browser. The ones using the twenty eleven theme are fine in Chrome, Safari and Opera but not firefox.

I can see this error in the logs File does not exist: …/public_html/wp-content/themes/twentyeleven/js/;return

which seems like it might be related somehow.