Installing floating floor and keep getting gaps
I haven't worked with the newer Pergo; the last I installed was in 2007.

However, check the installation basics (from here and here):


Are you installing in the correct direction?  The tongue facing upward should be on the floor and the next piece goes on top of it.
Is the floor flat?
Is the flooring material acclimated to between 65 &deg;F and 72 &deg;F for at least 48 hours?
Are you alternating seams so they are at least 12 inches offset from each row?
Are you not tapping from the sides?
Are you providing 1/2 inch clearance from the walls, pipes, and other fixed objects?  (3/8 is for rooms smaller than 40 feet.)
Are you damaging the tongues or seams?
Are you using T molding across the width of the room?  See the instructions for rooms longer than 40 feet.