[3D Max 5]Problem with rotating animation

[ztein]

Hi.

Trying to make an explosion with the folowing animation:

1.When a projectile hits the target the small sphere appears and starts to expand at the same time rotating.

2.When reached a certain size it will stop increasing in size and will keep rotating for some time.

3.Then it dissapears.

But when I try to preview the animation I get the displayed error messages.

What did I do wrong?

P.S.
Is it right to use "Stand" note for this type of model?

Thanks