I think that in the first method you forgot to decode the variables (that the purpose of using URLVariables class)

1. Use the following function to extract the query variables:

function getQueryParameter(variable) {
var query = window.location.search.substring(1);
var vars = query.split(“&”);
for (var i=0;i<vars.length;i++) {
var pair = vars[i].split(“=”);
if (pair[0] == variable) {
return pair[1];
}
}
}

2. Embed the *.swf using SWFObject, then call getQueryParameter(variable) and assign it the appropriate flash variable:

var flashvars = {
name1: getQueryParameter(“name1″),
name2: getQueryParameter(“name2″),
name3: getQueryParameter(“name3″)
};
var params = {
menu: “false”
};
var attributes = {
id: “myDynamicContent”,
name: “myDynamicContent”
};

swfobject.embedSWF(“myContent.swf”, “myContent”, “300″, “120″, “9.0.0″,”expressInstall.swf”, flashvars, params, attributes);

Cornel.

you can also use swfObject. It provides a nice way to send Variables to a Flash app, be it URL-Variables or hardcoded values inside the html.
you can find this here:
http://code.google.com/p/swfobject/