Please try disabling the world filter for buddy messages, located in the General Tab of the Zone Configuration.
Also please update to the latest SFS2x RC3, i'm pretty sure this issue was already fixed.
SFS Pro/Basic, SFS2X, AS2.0/AS3.0, Java, HTML5/CSS3/JSSFS Tutorials: http://sfs-tutor.blogspot.com/
- I no longer update it nor visit it. Some examples may be bugged.
If I take too long to reply, feel free to PM me