You'll also need to edit the functions fetchRadarImageIndex and radarImageIndexPageFetchComplete. In those functions, change www.srh.noaa.gov to radar.weather.gov.
This is an awesome widget and unfortunately NOAA can't seem to keep their URLs and such static. I used to work there, so this doesn't surprise me!! :)
To get this widget working, you'll need to download the widget file, open it with WinZip (or use unzip on the Mac), and edit the Stormy Weather!.kon file. Find the definition for the station array and capitalize all of the 3 character station abbreviations. Zip it all back up and install.