Drawing an array onto the screen, at a specific frame in a spritesheet

[mxa92]

I keep running into errors when I try to draw an Array onto the screen using a specific section of my Sprite-sheet.

Here's the code I have to actually create my sprite-sheet:

#fields
// Fireball variables
        private Point frameSize6 = new Point(48, 47);      // Fireball image size
        private Point currentFrame6 = new Point(0, 0);     // Start frame
        private Point sheetSize6 = new Point(1, 6);        // Spritesheet size
        private int noOfFireballs = 15;                    // Total number of fireballs to display
                                       
        Vector2[] fireballPos;                            // Position of fireball(s)

        private int timeSinceLastFrame = 0;
        private int milliSecondsPerFrame = 500;           // 2 Frames Per Second (fps)


#initialisation
// Setup Fireballs
            fireballPos = new Vector2[noOfFireballs];         // Position of fireballs

private void resetGame()
{
            for (int i = 0; i < noOfFireballs; i++)          // Keep looping until each Fireball has been given a position                                   
            {
                fireballPos[i].X = Math.Max(0, rand.Next(gameWidth) - frameSize6.X);             
                fireballPos[i].Y = Math.Max(-500, rand.Next(gameHeight) - frameSize6.Y);                 
            }
}

        public override void LoadContent()
{
spriteBatch = ScreenManager.SpriteBatch;
fireballs = content.Load<Texture2D>("Graphics/Sprites/fireballs");
}

#update and draw
...

I can draw the entire sprite-sheet onto the screen by using:

for (int i = 0; i < noOfFireballs; i++)
            {
                    spriteBatch.Draw(fireballs, fireballPos[i], Color.White);                       
            }

but it doesn't seem to use the current frame I specified.. :S
How would I go about doing this?
Thank you