Please give us more information about your Creative environment:
What version of Flash Professional are you using? And, if applicable, include the minor version number (e.g., After Effects CS5.5 with the 10.5.1 update).
What operating system? This should include specific minor version numbers, like "Mac OSX v10.6.8"---not just "Mac". Also, see this page to quickly check if your OS is supported for the version of Flash Professional you are using.
Tell us about your computer hardware. Include CPU type and number of processor cores, amount of RAM installed, GPU, number of disk drives, and how any external drives are connected.
If you are getting error message(s), what is the full text of the error message(s)?
If you encountered a crash, please upload Flash Professional log files to any free file sharing sites and post a link. Depending on the OS you are using, you will find the crash logs at:
Win: Program Files\Common files\Adobe\Installers or \Documents and Settings\<user>\Local Settings\ApplicationData\Adobe\AAMUpdater\1.0\
Mac: /Library/Logs/Adobe/Installers or ~/ Library/ApplicationSupport/Adobe/AAMUpdater/1.0/