I think you'd better use the mailing submission system run by MOLPRO.

You can use Molpro to generate .molden file, and then load it into Multiwfn (http://sobereva.com/multiwfn) to perform spin density analysis.

The way to generate .molden file is described in the beginning of Chapter 4 of Multiwfn manual. In Multiwfn there are numerous ways to study distribution of spin density, for example, you can plot spin density as curve map, plane map, isosurface map. Also you can calculate spin population for atoms or ELF basins. Please consult Section 4.A.2 of the manual for detail.

For the simplest case, you can input below commands to obtain atomic spin population by Becke partition:

test.molden

15

1

5

The data under "value" column is atomic spin population.

In Multiwfn it is also possible to calculate atomic spin population by other methods such as Mulliken, SCPA, Hirshfeld, etc. Please contact me if you encounter problem.

The question is three years old, but maybe somebody finds this Molpro example useful, see https://www.molpro.net/pipermail/molpro-user/2014-December/006246.html