Using the AUM 4 snippets that Dlively posted, I've written this code
Code:
action RightMarkerAction()
{
	set(my, PASSABLE);
	my.blue = 100;
	my.ambient = 100;
	my.lightrange = 200;
	while(1)
	{
		FrontRightPos.x = your.x + (50 * cos(your.pan)) + (50 * sin(your.pan));
	    FrontRightPos.y = your.y + (50 * sin(your.pan)) - (50 * cos(your.pan));
	    FrontRightPos.z = your.z;
		vec_set(my.x,FrontRightPos);
		wait(1);
	}
}

action LeftMarkerAction()
{
	set(my, PASSABLE);
	my.red = 100;
	my.ambient = 100;
	my.lightrange = 200;
	while(1)
	{
		FrontLeftPos.x = your.x + (50 * cos(your.pan)) - (50 * sin(your.pan));
	    FrontLeftPos.y = your.y + (50 * sin(your.pan)) + (50 * cos(your.pan));
	    FrontLeftPos.z = your.z;
		vec_set(my.x,FrontLeftPos);
		wait(1);
	}
}

function CreateMarker()
{
	FrontRightPos.x = my.x + (50 * cos(my.pan)) + (50 * sin(my.pan));
	FrontRightPos.y = my.y + (50 * sin(my.pan)) - (50 * cos(my.pan));
	FrontRightPos.z = my.z;
	ent_create("box.mdl", FrontRightPos, RightMarkerAction);
	
	FrontLeftPos.x = my.x + (50 * cos(my.pan)) - (50 * sin(my.pan));
	FrontLeftPos.y = my.y + (50 * sin(my.pan)) + (50 * cos(my.pan));
	FrontLeftPos.z = my.z;
	ent_create("box.mdl", FrontLeftPos, LeftMarkerAction);
	wait(1);
}


Now I have two transparent boxes floating slightly in front of my entity, 1 to the left and 1 to the right. They visually represent the vector positions that will check whether my entity has bumped into a wall. I don't know how exactly to perform that check. The AUM used C-SCript and the check was done using
Code:
BooleanVar = content(VectorToBeChecked);
if(BooleanVar == content_solid) 
{ ObstcaleInThatDirection = 1;}

What's the lite-c equivalent of content() and content_solid?