When I insert a keyframe, Flash automatically creates a motion tween from the previous keyframe to my newly inserted one. Why is this happening?
When you insert a keyframe, Flash copies the previous keyframe (the contents and the frame settings). If the previous keyframe has been set to tween, the new keyframe will have the same setting.
Why can't I motion tween more than one symbol?
You can have multiple shapes inside the symbol you're tweening. But the rule is that you can use only one symbol per layer. You'll see in Hour 11, "Using Layers in Animations," that you need to separate each tweening symbol into its own layer.
When I use the Rotate setting in my keyframe, my symbol always rotates around the visual center, despite the registration point I chose when I created the symbol. How do I rotate around something other than the visual center?
The symbol rotates around the transform center point. Use the Transform tool to modify the axis of rotation for the instance. For more about this, review Hour 4.
Why doesn't my motion tween follow a smooth path?
Motion tweening can tween more than just position. When tweening position, Flash moves directly from one keyframe to the next, finding the shortest path between two points. Wouldn't it be cool if you could draw a curve and tell Flash to follow the path you drew? You can. This is called a Motion Guide layer, and it's covered in Hour 11.
I'm trying to use the Custom Easing dialog box to make my animation go past the end of its motion say, 120% of its tween. How can I do that?
You can't do it with just two keyframes. You can insert a new keyframe somewhere before the ending and place your instance in a location past the destination. Also, although it might not be appropriate for your case, be sure to consider doing this in a frame-by-frame animation. Quite often just a few strategically placed keyframes are more effective than a tween. Finally, you'll learn more about this technique called overkill in Hour 22.