Linecast not working

OK, I am using a mesh to check if there is a wall between one node and another node, something like this:

var layermask : layerMask;//layerMask is the layer named Walls
var nodes : Vector3[] = Grid.vertices;
if(!Physics.Linecast(nodes[actualnum],nodes[actualnum-1],layermask)){
//Only pass if there is nothing(walls) between this nodes
DoSomething();
//This is just a reduction, there is more but this is the important part
}

OK, for those how ask lots of things, My wall has a box collider and a layer named Walls and in the script the variable layermask I put Walls, then I have try to remove the !, add layermask.value, set the layermask variable of all except Walls and some many other things, but nothing works. Somebody can tell me what is wrong or what I miss. Please if someone have a question please comment, do not answer.

I have no idea if this could work... But could you do a ray cast from node to node, and if it reaches it, its TRUE, but if it doesn't, it's FALSE? I've never really seen a Linecast before, don't know what it does, but I thought of this when I read the first line... So you might not even be interested haha.

Maybe post a question with what you have right now... I personally don't know raycasts to well, so I'm not of complete help, but I'm sure someone can help =).