so the swfs open in FPlayer 6 fine right? They just have the Flash 5 icon?
Open up a folder and from the menu select
Tools > Folder Options…
Then select the File Types tab, browse down until you find swf
(its easier if you wait til the list loads, select the first one then press T on your keyboard, swf should be right above that).
Then select the swf file in the list and press the Advanced button below. If there is no Advanced, it should be restore, in which case you would want to restore it then choose Advanced.
This will open a new dialog for your file type allowing you to specify what opens it as well as other commands (which can be accessed by right-clicking on a file of that file type) as well as the icon used to represent that file type. The Flash 6 .swf icon is loacated in your Flash.exe application file in your Flash MX folder, so browse there and select Flash.exe to view the icons in Flash’s library. select the swf icon, hit ok and apply apply apply. It should all take effect after you exit the Folder Options dialog (or maybe before that)