Issues w GeoMac GeoRSS Feed

Hello,

So far I have been able to create GeoRSS feeds from the following sources:

MODIS GeoRSS Feed
USGS Earthquake GeoRSS Feed

However I have not been successful with creating a GeoRSS feed via the data source from GeoMac:

GeoMac GeoRSS Feed

I keep getting the following error messages:

Fault code: Channel.Security.Error
Fault info: Security error accessing url
Fault details: Destination: DefaultHTTP

Has anyone been able to use the GeoMac data?
Does anyone have any suggestions?

If anyone can get the GeoMac feed shown above to work, please respond.

Thanks,

George

Viewer for Flex 3.6
ArcGIS 10.2