I set my movieclip can be drag,mostly it's ok.
but sometimes, maybe when keep drag and drop ,drag and drop the movieclip,it will show the error message:

/mygame/movieclip.lua:195: attempt to perform arithmetic on field '_startX' (a nil value)

it's a simple movieclip even no animation.

can I fix this problem ?

thanks.

Can you post your code to give us a better view?