Supported mp3 bitrates?

Hi all,
I’m currently working on a project where I have mp3 files externally loading into my SWF, but they are playing at twice the speed they should be. I’m wondering if there are some ‘safe’ compression rates that I need to use–or what are some unsafe bitrates. Right now I have them compressed at 32kbps 32kHz mono. It’s not agreeing with Flash. if there is some kind of list of all the safe audio formats and settings, please let me know. that’d be a mighty handy list.

Any help is much appreciated.
thanks in advance,
Dave