Assuming you get the "value" parameters from aweber it actually looks fine. I believe that the ejunkie php script called (o_plug.php) recognizes the parameters as belonging to aweber and passes it on accordingly.
I do see though that you are experiencing what I think is an eJunkie bug.
in between the "o_plug.php" and the "meta..." you need to have a "?&" as detailed on this page:
http://www.e-junkie.com/ej/help.integration.php.
Unfortunately, at least with my configuration, I can't even type those characters in the field.
Can you? Without them your values won't get passed along.