Line 33: deltap = ((0.5param.F)./(param.RT(param.Nal+1:param.Nal+param.Np))).(Phis(1:param.Np)-Phie(1:param.Np)-U_p);
should be:
Line 33: deltap = ((0.5param.R)./(param.FT(param.Nal+1:param.Nal+param.Np))).(Phis(1:param.Np)-Phie(1:param.Np)-U_p);

Same for Line 47 for deltan