please help T.T
The following Flash forum posting may help answer your question:
The "correct" answer suggests saving the Fireworks file as a PSD and then importing that PSD into Flash. I'm not very familiar with this workflow. You might also try exporting the Fireworks file in the FXG format (File > Export..., then choose "FXG and Images"), then importing the FXG file into your Flash library.
Hope this helps!
P.S. Do you still have CS5? If so, you could copy-and-paste directly into Flash CS5, and then from Flash CS5 to CS6.