33 MB is alot for flash. I would try to create sevral SWF and then use the loadmovienum() to load them on diferent layers.
Aslo make sure you have a stable system. It kinda sounds like a RAM issue maybe. What kind of system arte you useing and what do you have running when you open the FLA or SWF. Close your TSR's and try it then.
Hope this helps.