CDO

hi,
i want to combine multiple netcdf files into one file.i have taken a test before do it.
my two netcdf file info is as following:
file 1:

ncdump -h GLDAS_LWdown.201112311800.365.001.nc
netcdf GLDAS_LWdown.201112311800.365.001 {
dimensions:
scalar = 1 ;
time = 1 ;
lat = 600 ;
lon = 1440 ;
variables:
float EDGEW ;
EDGEW:long_name = "western edge in atmospheric data" ;
EDGEW:units = "degrees_east" ;
EDGEW:mode = "time-invariant" ;
float EDGEE ;
EDGEE:long_name = "eastern edge in atmospheric data" ;
EDGEE:units = "degrees_east" ;
EDGEE:mode = "time-invariant" ;
float EDGES ;
EDGES:long_name = "southern edge in atmospheric data" ;
EDGES:units = "degrees_north" ;
EDGES:mode = "time-invariant" ;
float EDGEN ;
EDGEN:long_name = "northern edge in atmospheric data" ;
EDGEN:units = "degrees_north" ;
EDGEN:mode = "time-invariant" ;
float LATIXY ;
LATIXY:long_name = "latitude" ;
LATIXY:units = "degrees_north" ;
LATIXY:mode = "time-invariant" ;
float LONGXY ;
LONGXY:long_name = "longitude" ;
LONGXY:units = "degrees_east" ;
LONGXY:mode = "time-invariant" ;
float FLDS ;
FLDS:long_name = "incident longwave radiation (FLDS)" ;
FLDS:units = "W/m2" ;
FLDS:mode = "time-dependent" ;
FLDS:_FillValue = -999.f ;
}

file 2

ncdump -h GLDAS_LWdown.201112312100.365.001.nc
netcdf GLDAS_LWdown.201112312100.365.001 {
dimensions:
scalar = 1 ;
time = 1 ;
lat = 600 ;
lon = 1440 ;
variables:
float EDGEW ;
EDGEW:long_name = "western edge in atmospheric data" ;
EDGEW:units = "degrees_east" ;
EDGEW:mode = "time-invariant" ;
float EDGEE ;
EDGEE:long_name = "eastern edge in atmospheric data" ;
EDGEE:units = "degrees_east" ;
EDGEE:mode = "time-invariant" ;
float EDGES ;
EDGES:long_name = "southern edge in atmospheric data" ;
EDGES:units = "degrees_north" ;
EDGES:mode = "time-invariant" ;
float EDGEN ;
EDGEN:long_name = "northern edge in atmospheric data" ;
EDGEN:units = "degrees_north" ;
EDGEN:mode = "time-invariant" ;
float LATIXY ;
LATIXY:long_name = "latitude" ;
LATIXY:units = "degrees_north" ;
LATIXY:mode = "time-invariant" ;
float LONGXY ;
LONGXY:long_name = "longitude" ;
LONGXY:units = "degrees_east" ;
LONGXY:mode = "time-invariant" ;
float FLDS ;
FLDS:long_name = "incident longwave radiation (FLDS)" ;
FLDS:units = "W/m2" ;
FLDS:mode = "time-dependent" ;
FLDS:_FillValue = -999.f ;
}

--------------------------------------------------------------
then i cdo cat these two files , the following info appeared:

cdo cat GLDAS_LWdown.200112311800.365.001.nc GLDAS_LWdown.200112312100.365.001.nc out.nc

cdo cat: Open failed on >GLDAS_LWdown.200112311800.365.001.nc<
Unsupported file type (library support not compiled in)

can anybody tell me how to resolve it?

thanks