On further examination, it is clear that there is rather bizarre non-deterministic server behavior. Sometimes when I run ncdump on that url, I get the server error message (as expected). However, occasionally, the server instead returns a DAP dds with two fields of the same name, and this causing netcdf DAP code to fail; weird! =Dennis Heimbigner Unidata Ticket Details =================== Ticket ID: VEW-543105 Department: Support netCDF Priority: Normal Status: Closed