_sans shows no text

I thought that there is no need to embed a font when I use _sans. I’ve used it a couple of times and it works avery time…

Except this time…when I use embedded Arial of even embedded _sans, the text appears the way I like it. Does anyone know why _sans does not work this time?

(add. info: the text has to appear in an external swf. but this shouldn’t matter…right?)