ExternalInterface.call() does not work normally since flash player 11.8.800.168

Problem Description:

korean character crash when using ExternalInterface.call(funcName, args)
     funcName : alpha-numeric
     args : include korean characters

Steps to Reproduce:

<flex source>
private function handleRequest(val):void {
     ExternalInterface.call("processRequest", "가나다라");
}

<javascript source>
function processRequest(param) {
     alert(param); //does not display korean characters
}

Actual Result:
     媛&#128;?섎떎??

Expected Result:
     가나다라

Any Workarounds:
Nothing !!

OS : Windows7 Pro 64bit(korean)
Flex Builder : 3.0
Flash Player : 11.8.800.168 ActiveX
Browser : IE10
WAS : WebLogic 8.1, 12g, Tomcat 5,6,7

Chrome : 29.0.1547.66 m <== Good
FireFox : 23.0.1 <== Good