Rotation between two Position Vectors

Okay I am in a little bit of a quandry. Given two position vectors. PosA and PosB, I need to find the 4 float rotation needed to rez an object that goes from PosA to PosB

Here is what I have.... it is not working

person=(llDetectedPos(i));
llSay(0, "Targeting " + llDetectedName(i) + " at " + (string)person);
llLookAt(person, 32727, 32727);
cnt=0;
eul= ((llGetPos()) - person);
eul *= DEG_TO_RAD; //convert to radians
vector b = llGetPos();
rotation a = llEuler2Rot(eul);
vector c = llRot2Fwd(a);
vector d = llRot2Up(a);
b += c;
b += d * 1;
c *= 65;
do
{
cnt++;
//llSay(0,(string)cnt);
llRezObject("NewBB", b, c, a, 0);
}
while (cnt < 3);

LSL has that built in: llRotBetween()

Maybe I should have been more detailed.

I need to rez object going from GetLocalPos() to llDetectedPos(i)....

Do you mean, like... rez a prim oriented to the angle of travel, and scaled so that the faces of the prim meet both points?

Or is this just a bullet, and you need the bullet pushed toward point B from point A?

rotation vector2rot( vector Vector ) { 

    vector forward = llVecNorm( Vector ); 
    vector left; 
    if( (forward.z > 0.9999) || (forward.z < -0.9999) ) { left = llVecNorm( <1.0, 0.0, 0.0> % forward ); } 
    else                                                { left = llVecNorm( <0.0, 0.0, 1.0> % forward ); }

    return llAxes2Rot( forward, left, llVecNorm( forward % left ) ); 
} 

returned rotation will make the X+ side of object 'aim' in the direction of provided vector, if i recall right. If the rezzing object is rotated, you might need to cancel it out through dividing the provided rotation by rotation of rezzing 'parent' object.