Javascript :: Send A JSON Command To The Company's Flash Player?

I've ran into a weird problem while trying to send a JSON command to my company's flash player. Basically, i am unable to pass a playlist to this player - nothing happens - using the following command:

player.sendEvent("LOAD_PLAYLIST", json_str);

but the weirdest part is that if I print the entire command using Firebug's console.log, copy it and paste it into the code (thus hardcoding the playlist), everything works like a charm.

For instance, the following code:

player.sendEvent("LOAD_PLAYLIST", "{"streams": [{"src": "rtmp://xxx.xxx.xx:80/redirectvodxxx/nas2.share/h264/512x384/progname1/prog_1_20110804.mp4"},{"src": "rtmp://xxx.xxx.xx:80/redirectvodxxx/nas2.share/h264/512x384/progname2/prog_2_20110804.mp4"},{"src": "rtmp://xxx.xxx.xx:80/redirectvodxxx/nas2.share/h264/512x384/progname3/prog_3_20110804.mp4"}]}");

was obtained using

console.log('[loadNewListofContents] playing the following content list: player.sendEvent("LOAD_PLAYLIST", ' + json_str.toString() + ');');

and if i hardcode it, it works!I've tried all the toString() tricks I can think of (ex: json_str.toString(), '"' + json_str.toString() + '"', etc...) but so far no such luck.