flash_php_email (kirupa tut) > message field does not stress words

I am considering the possibility of using the flash + php form (http://www.kirupa.com/developer/actionscript/flash_php_email.htm) , and during the tests I noticed message field does not send send messages correctly when words stressing is needed (á à , é , í , ó , ão ) ;
I received strange characters when typed stressed words :

á é i ó u ão à pão cão árvore ;

what has to be changed on the code to allow stressing ??