Nope. The slam attacks aren't magical attack so they don't do anything to incorporeal creatures.
Incorporeal: Creatures with the incorporeal condition do not have a physical body. Incorporeal creatures are immune to all nonmagical attack forms. Incorporeal creatures take half damage (50%) from magic weapons, spells, spell-like effects, and supernatural effects. Incorporeal creatures take full damage from other incorporeal creatures and effects, as well as all force effects.
Now, if you had an amulet of mighty fists that would make all your natural attacks (including slams) magical, and thus able to deal damage to Incorporeal creatures.
That said, the burn damage that the slams deal would affect the elemental.