Send an error if the data files are missing
Send an error if the data files are missing

chemfiles/chemfiles,Luthaf/Chemharp,lscalfi/chemfiles,Luthaf/Chemharp,chemfiles/chemfiles,chemfiles/chemfiles,lscalfi/chemfiles,lscalfi/chemfiles,chemfiles/chemfiles,Luthaf/Chemharp,lscalfi/chemfiles