Security Sandbox Violation when transforming mc inside onLoadInit

programming flash
1

I’m trying to load an image into a placeholder movieclip, using movieClipLoader.loadClip.
When the onLoadInit event fires, i do some resize and alpha fade-in code. The resize code causes Security Sandbox Violation. This is the culprit:

if(frame2picRatio<=1){
mat=target.transform.matrix;
mat.scale(frame2picRatio,frame2picRatio);
target.transform.matrix=mat;
}

When I comment it out in the onLoadInit, the error goes away. I don’t know what connection is there between scaling a matrix and Security Sandbox.

Any thoughts?