If laminate was Superman, humidity and water would be its kryptonite. In other words, a steam cleaner and laminate would be a fatal combination. Steam cleaners produce moisture and heat and water that will surely wreak havoc on your laminate floors.
Flooring professionals do not even recommend wet mopping laminate. When cleaning your laminate floors, sweeping and mopping with a damp mop are the only methods that are generally advisable. If there are only some small problem areas, you may want to consider cleaning them by hand with some alcohol and a clean cloth. When cleaning by hand you can better control the amount of liquid that you're putting on the floor.
I've seen various websites where many people recommend steam cleaning laminate floors. They obviously have never tried to personally steam clean laminate before. If you want to protect the longevity and performance of your laminate floors, keep them clear of water and extreme humidity change at all costs!