Pr3+ ion SCF calculation using Stuttgart large core ECP gives 'atomscf' error

You can fix this problem in two ways.
1) Use a basis with f orbitals (since the atomic calculation on Pr neutral is crashing when looking for an f shell to fill) or
2) Use the 1-electron hamiltonian as starting guess using the input lines

scf
 vectors input hcore
end

http://nwchemgit.github.io/index.php/Release66:Hartree-Fock_Theory_for_Molecules#VECTORS_--_...