ActionScript 3.0 :: Passing And Receiving Of Variable From One Class To Another?

My problem is when I try to make both class receive and send. It doesnt work.Here IF ONLY ONE CLASS SEND and 1 CLASS RECEIVE it works

Class A variable a ---> Class B variable _a; WORKS

Using this code:

My class A

ActionScript Code:
package  {
import flash.display.MovieClip

[code]....

But when I try to make them both receive and pass it says

Quote:

Error: Error #2136: The SWF file file:///E|/Andrew%20Documents/ColiisionDetection%20Kit/New%20Folder/passingandreceiving.swf contains invalid data.
at CLb()
at CLa()

Here is the code when they both receive and pass.

Class A

ActionScript Code:
package  {
import flash.display.MovieClip
import CLb;

[code]....