I have this bug while trying to test RegCM4.6.0

Opening /mnt/lustre/users/jakinyoola/regcm/run/REGCM_GLOBEDAT/SURFACE/GMTED_DEM_30s.nc

 NetCDF: Unknown file format                                                    
 mod_rdldtr.F90 :      141:NetCDF Error:          -51

what do I need to do correctly

Julius