JS ExternalInterface calls crashes Flash player


We build a flash application in ActionScrip 3 which provides JS external interface calls. We load another swf on our swf. If we don’t enable external swf, any JS calls through external interface works fine. However, if external swf is active, at some points when there is any JS calls through external interface, Flash player plugin crashes which also bring down the whole browser, I see that on IE and FF.

Do you have any idea what may cause external interface call to crash Flash plugin?