Help for Super Paper Mario on Wii?

Question

I got the fourth pure heart now where do I find the pillar?!?!?

Answer 1

After speaking with Merlon, run left to the edge of the platform and activate the elevator where the red arrow faces down.
After arriving at the second floor of Flipside, follow Tippi to another elevator on the right and ride it up to the third floor. Now get near the Heart Pillar on the far left to place the Pure Heart and make a door appear near Merlon.
Now return to Merlon via the same route you took to get to the Heart Pillar: Take the elevator back down to the second floor, then the one left of there to get back up to Flipside's Tower, where Merlon awaits.
Merlon will inform you of the "Dimensional Door" that has just appeared as a result of placing the Pure Heart into the Heart Pillar. This door leads into the first world, where you'll find another Pure Heart at the end. Merlon will also gift you a Return Pipe, which grants Mario the ability to return to Flipside from almost any location.
Proceed through the Dimensional Door into World 1.

Answer 2

you head up to the 2nd Floor of Flopside, you’ll come across a flipped Merlon, who calls himself Nolrem. He’ll tell you that there’s a new Heart Pillar on the 3rd Floor of Flopside, and indeed there is. Find it, insert the Pure Heart, and a new door will open on the top part of the White Tower. If you head all the way to the left side of Flopside 2nd Floor, you can get Welderburg to make you a pipe between that area and Flipside, but it’ll run you 300 bucks. Otherwise, return back through the Mirror Hall and head up to the roof to find the new door to Chapter 5.

Courtesy of gamespot.com