How do you get past wall of light in almia castle?

If you mean the wall of light in the Almia Castle, with the two Riolu statues by it, then here's how. First go to this ice path, ( the part where you slide against the ice and the ice will fall down after you touch it ) Go to the left or the right, depending on which direction you choose. Doesn't have to be in direct order. Go to the direction you choose. After you go for midway, you should see a closed door with a green carpet on solid ground. Go for the doorway, this part's the hard part. Steering is essential in this part, you should turn before you hit the edge because of the slippery ice, you'll fall off the edge. After you do, explore the room and you should find Riolu. Capture Riolu then go back to the ice path. Go back to where you started then go the opposite direction you went, and do the exact same thing. When you catch the other Riolu, go to the room where the light screen is, and if I remember correctly, you shall see the leader of the Sinis Trio, Ice. He will challenge you, and as added effect, he will call you a 'noob'. I haven't tried it as a guy, so I don't know if he'll call you a noob if you're a guy. Anyways you will catch his Froslass, and he will flee. (If I remember correctly, I haven't played it in a long time.) Then you will run into the wall, and you will be asked if you want to use your Riolu's power. Say yes, and the wall will disappear. Go into the doorway. You should be in an ice cave. *Spoiler, if you don't want to ruin the surprise don't read, just look at the save machine part*

I suggest you save your game with the save machine at the end of the cave. *Real spoiler part starting*

Rythmi will call you and tell you a powerful Pokemon is awaiting you. Go out of the cave ( at the other end of course ) and you will see a barrage of non-lit torches. You should go halfway, and the torches will light. Then a Pokemon will appear before you, it's the Guardian of the Prince's Tear ( Or something like that if I remember ) It is Lucario. You will capture Lucario, or at least attempt to. Lucario is very strong, I wish you luck. Took me around 4 times to catch him. After that Lucario wiill trust you with the Prince's Tear and you will probably report back to base.

GOOD LUCK,

HEATHER.