[netcdf-java] Server requirements for aggregation through HTTP service?

NetCDF-Java gurus,

Are their server requirements for aggregation through HTTP service?

This NcML file works:
http://stellwagen/models/test/umb_aggregate2.ncml

This NcML file doesn't work:
http://stellwagen/models/test/umb_aggregate3.ncml

and the only difference is the HTTP server location.

Sorry for the bombardment of questions -- I've got a talk tomorrow at
noon on model interoperability and I'm showcasing NcML/THREDDS/NetCDF
Java!

-Rich
-- 
Dr. Richard P. Signell   (508) 457-2229
USGS, 384 Woods Hole Rd.
Woods Hole, MA 02543-1598