For the OnInit event command, you must have the NPC on your screen, otherwise it does nothing.
Try this:
caspen,0,0,0<TAB>script<TAB>Supporter1#supp1-1<TAB>-1,{
OnInit:
setcell "caspen",0,0,300,300,cell_basilica,1;
end;
}
PS: I'm not sure if 'cell_basilica' even works for monsters...