Font display problem - swf within an swf

I’m modifying a project written in Flash MX and Actionscript2.

This consists of a main swf file in which another is embedded.
The inner swf generates text fields dynamically in as2 using fonts embedded in the flash document.

This works perfecly when the inner swf is displayed on it’s own but in the context of the main swf no text is displayed.

We’ve demonstrated that the code generating the text runs in this context and that a similar behaviour occurs using builtin fonts.

Please can anyone advise how this can be resolved?

An extract of the code in use:
// this is a font embedded in the .fla, exported for actionscript and into the first frame
var font:String = “EmbeddedFont”;
this.fmt= new TextFormat();
this.fmt.font = this.font;
this.fmt.size = this.fontsize;
this.fmt.color = this.color;
this.tf= this.mc.createTextField(GUID.create(), this.depth(), this.x, this.y, this.width, this.height);
this.tf.html = true;
this.tf.text = this.text;
this.tf.html = true;
this.tf.autoSize = true;
this.tf.setTextFormat(this.fmt);

[FONT=&quot]where GUID.create() returns an unique id and this.depth() returns mc.getNextHighestDepth()[/FONT]