I am querying a list of attachmens and displaying the list below the file upload section of the page. 

In the list I want a URL to view the file in a new window. (The built in RelatedList does not perform the same).

On the controller I attempt to get the URL with :

@RemoteAction
global static String getFileURL(String id){
try {
                   fileURL = URL.getFileFieldURL( id ,'AttachmentBody');
                   return fileURL;
}catch(Exception ex){
                   fileURL = ex.getMessage();
                   return fileURL;
}

}

The call to URL.getFileFieldURL fails with an Invalid Parameter value for the fieldName - this is exactly as per the documentation code

Any ideas would be helpful

thanks

Joe