Error 12 running problems

The .out file ends with the relevant error message:

  **** Low energy neutron xsec not found for some media            5           9  ****
 phos    
 sulf    
 clo     
 pot     

In the respective elemental MATERIAL definition [by the way: do not fill the Am field, as prescribed in the manual, nor fill the A field, since you do not want a (radioactive!) mono-isotopic composition], you should give a case sensitive name matching the one in the low energy neutron library (e.g., PHOSPHO, and not phos).
Otherwise, you could ask for the new point-wise treatment instead (by means of an empty LOW-PWXS card), requiring to download the respective libraries.