Tim,
I am pretty sure this is the cause …
The version of the wxflyer you installed requires the rss-advisory.php must be at version V2.00 06-Jun-2009 BETA .022 or higher
You can get that here:
NOAA RSS Advisory 2009 PHP script
http://discourse.weather-watch.com/t/40732
Upgrade your rss-advisory.php to the Beta 2.00 version
Download the Beta version:
http://www.642weather.com/weather/rss-advisory-2009.php?sce=view
rename the beta script to rss-advisory.php