Michael Silverbane
Adventurer
What it will block is Force effects and Ghost Touch items.
So anyone with Mage Armor up, or wearing Bracers of Armor (which uses the same spell) will have a problem. The wall doesn't affect the Material plane, the Force effects and Ghost touch items affect things on the Ethereal, where the wall is.
Ghost touch items don't affect ethereal things, only incorporeal ones. Force effects (when originating from the material plane) extend into the ethereal, as well as affecting incorporeal creatures.
So... The wizard with mage armor up would bump into the ethereal wall, but the fighter wearing a ghost touch sword would not.