Due to a change to the Java Runtime version 7u51, an error message states that the application is blocked by security settings when trying to load the file manager. This can be prevented by adding the address of the Webmin to the Exception Site List in the Java Control Panel.
 
Please proceed as follows:

1. Open the Java Control Panel in Systems|Java.
2. Select the tab "Security".
3. Click the "Edit Site List..." button.
4. Click "Add" in the "Exception Site List" dialog.
5. Enter the Webmin address, e.g. "https://licensecentral.company.local:10000".
6. Click the "OK" button.
7. Click "Continue" to acknowledge the security warning.
8. Click "OK" to close "Java Control Panel".

When starting the file manager for the first time the security warning "Do you want to run this application?" is displayed.
Click "Run" to start the file manager.