I just noticed this today. If you start typing $_SERVER in Dreamweaver, you get a code hint for $_SERVER. Then, once you have that it has server variables, one being HTTP_REFERER. Now, if you select that one, though it says HTTP_REFERER in the code hint, once its placed on the screen its as HTTP_REFERRER with an extra R :sure: Crazy typos! You can easily fix this yourself by opening the code hints XML file in
C:\Program Files\Macromedia\Dreamweaver MX\Configuration\CodeHints
(or equivelent)
and searching from HTTP_REFERRER replacing it with HTTP_REFERER. Save, restart Dreamweaver MX and you’re good to go.
That one screwed me over for a little while there 
