error message when exporting animation

Appologies if this is in the wrong place:o:o:o:o
Trying to export a bit of animation but I keep getting this error message:-
'failed to tween object (file name)
blend error it's not possible to have nested tween names between frames n/a and frame one'
What does it mean and what should I do?

To create a Flash animation using a tween you have to name the shape. The copy & paste it onto another frame, move, rotate, shrink etc to get the animation to tween.

Without seeing your xar file it's hard to say anything further.