texture problem

I baked my Shadow map to this room, everything works fine till I put the texture on my walls, look some artifacs appear but I donesn t understand why.
Help, please!

Came on guys nothing close to this never show up on your works, I really need a hand here.
Help meeeeeee!

subdivide the wall, it;s because of the fact that light is calculated by vertices i guess!

tnks I ll try here, thanks again