I'm stuck in path of ligth 6F, I found a map on that says me how to proceed
here the image-> http://chaosmemo.net/bunnyblack2/dungeon/image/12.png
But in the middle of E5 and F5( on the map i send above ) have a wall and I don't know how to get through that.
Can you help me?

You need to go deal with Kasha I think it is? You should have seen some scenes with a guy and a tanned beast girl coming to the castle. They intend to shoot the castle with a beam, and you have to stop that before you can fight Ultinia. That wall opens up once you fight and beat the beast girl.

So if you haven't, find a purple enemy which will be the guy and win the fight. After that you should get a key to another dungeon area. The dungeon is Sentry Spear, where you want to get to the third floor to beat the beast girl. Then the wall between E5 and F5 will open up.

Did you beat Oldeus? If yes, then did you beat Kasha?

Yeah, it worked.
Thanks, I though that I needed to beat Ultinia before.

I beat Odelus then went and beat Kasha.

After that i went to Citadel Spear and saw Odelus got killed.

What to do next ? The wall in PoL 6f still there.