attachMovie syntax doesn’t work with Action Script 3.0. Each movieclips are considered as classes in Actionscript 3.0
Step 1: Insert Symbol -> Type MovieClip , Select export for actionscript
Step 2: Make a Note of the Class name
Step 3: Drag texttool and put some static text
Step 4: In Frame 1 paste the below code.
|var MC:Symbol1=new Symbol1() //Symbol1 is the classname for the movieclip