Changed error text to be clearer.
Changed error text to be clearer.

CENDARI/atom,CENDARI/atom,kyfr59/atom-cg35,kyfr59/atom-cg35,artefactual/binder,kyfr59/atom-cg35,artefactual/atom,artefactual/binder,Surfrdan/atom,CENDARI/atom,artefactual/atom,artefactual/binder,artefactual/atom,Surfrdan/atom,Surfrdan/atom,artefactual/binder