In V9.05, when saving a field in a output file, you can pack (compress) its value (l_out_pack=.true.)

If you got this error,

Erreur : routine = ionc4_locbounds , fonction : nf90_put_var
, variable : .
Erreur : routine = ionc4_locbounds , fonction : nf90_put_var
, variable : .
ERROR:
NetCDF: Numeric conversion not representable
ERROR:
NetCDF: Numeric conversion not representable
Well, the error message is not explicit... I agree.

This error means you try to write a field with the packing option to save disk place (l_out_pack=.true.). But a value (of more) of its field is out of the [riog_valid_min_var riog_valid_max_var] range.
Run again without l_out_pack and check which variable has values out of the [riog_valid_min_var riog_valid_max_var] range. riog_valid_min_var and riog_valid_max_var are assigned in paramain.txt
Modify the riog_valid_min_var and riog_valid_max_var variables and run again with l_out_pack.