Quaternion Error, what does it mean?

When I run a 'floating' script I get this error.

Quaternion To Matrix conversion failed because input Quaternion is invalid { -1.#IND00, -1.#IND00, -1.#IND00, -1.#IND00}

The scripts I'm running are concerning a ball. The ball has two scripts:

BallMove:

var moveforce = 5.0;
private var vecmove = Vector3.zero;

function Update () 
{

vecmove = Vector3(Input.GetAxis("Horizontal") ,0 , Input.GetAxis("Vertical"));
vecmove.x *= moveforce;
vecmove.y *= moveforce;
vecmove.z *= moveforce;
rigidbody.AddForce(vecmove);

}

Float

var waterLevel = 0;
var floatHeight = 0;
var buoyancyCentreOffset = Vector3.zero;
var bounceDamp = 0.2;

function Update () 
{
var actionPoint = transform.position + transform.TransformDirection(buoyancyCentreOffset);
var forceFactor = 1 - ((actionPoint.y - waterLevel) / floatHeight);

if (forceFactor > 0) 
{
var uplift = -Physics.gravity * (forceFactor - rigidbody.velocity.y * bounceDamp);
rigidbody.AddForceAtPosition(uplift, actionPoint);
}
}

The ball is a rigidbody. I'm using Javascript but the 'Float' script is adapted from C#. What does the Error mean?

The error means that some internal calculation went wrong and the result is now a value of -infinity. Common causes for this are 0-divisions. My guess would be that your offset is set to zero and transformdirection can't deal with 0-length directions, but that's only a guess.