Here's a useful article with information about using Flashvars in both AS2 and 3:
http://www.dreamincode.net/forums/to...n-as2-and-as3/

Since you are using SWFObject, you can ignore the HTML portion and skip down to AS2.
You will basically be accessing the variable as a property of the _root object, and using that to load the path.

Hope that works for ya!