[if !vml][endif]

Each keyframe in this animation is associated with a different symbol. You need to select one symbol in your library that will perform the animation rather than having two symbols performing the animation.

Select one of the symbols and rename it.

Example( graRedball )

[if !vml][endif]

Make sure your play head is located on the frame you would like to convert. Select the symbol located on your stage.

Go to your properties panel and select the Swap button.

A swap symbol panel will appear. Select the symbol you would like to swap (graRedball) and hit OK.

[if !vml][endif]

At this point you are no longer using your excess symbol (Tween2) so you can throw it away.

Select the options button within your library. Press the Select Unused Items button and delete your unused symbols.