This is just an example and it applies to all Unity3D content in both Chrome and Safari on OSX 10.6.4. Not sure when it stopped working, but its not working right now.
Was this fixed? I have a problem that looks similar. Not sure it is exactly the same though.
This is the web player log. The player ran in Safari 5.0.1 on OS X 10.6.4.
100904 00:45:48 Datafile file:///Users/carlemail/Projects/01%20now/Happy%20New%20Ears/02%20production/04%20software/Unity/Build/Web/100903/player.unity3d
100904 00:45:49 Loader: Start Success
100904 00:45:56 Instance 13fe6a6688e2a4ab0aab0ecc44fbcf1f shutting down
100904 00:45:56 loader: attempt unload reloable
100904 00:45:56 loader: Successfully made loader reloadable
100904 00:45:56 Datafile file:///Users/carlemail/Projects/01%20now/Happy%20New%20Ears/02%20production/04%20software/Unity/Build/Web/100903/player.unity3d
100904 00:45:56 UnityPlayerLoading: Loading failed, trying in temp directory
100904 00:45:59 Loader: Start Success
100904 00:48:58 Instance 4ff9783fa4ca142658edae35e43d5864 shutting down
100904 00:48:58 loader: attempt unload reloable
100904 00:49:02 loader: Successfully made loader reloadable
100904 00:49:02 Datafile file:///Users/carlemail/Projects/01%20now/Happy%20New%20Ears/02%20production/04%20software/Unity/Build/Web/100903/player.unity3d
100904 00:49:02 UnityPlayerLoading: Loading failed, trying in temp directory
100904 00:49:03 Loader: Start Success
100904 00:49:24 Setting error display: 'The content was stopped because a fatal
content error has been detected.', details: 'The content was stopped because a fatal
content error has been detected.', link: 0
100904 00:49:24 Setting error display: 'The content was stopped because a fatal
content error has been detected.', details: 'The content was stopped because a fatal
content error has been detected.', link: 0
100904 00:49:24 Setting error display: 'The content was stopped because a fatal
content error has been detected.', details: 'The content was stopped because a fatal
content error has been detected.', link: 0
“I believe what you are experiencing is a bug that is happening at the moment with unity and the latest update for OSX. Our fix for this will be out very soon.”