Invalid Email Address: Undefined

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Trying to subscribe 

What is the expected output? What do you see instead?
The expected output is seing a message that the subscription succeeded, 
but instead it says Invalid Email address below the form, and "undefined" 
appears in the text field.

What version of the product are you using? 
Version 1.0 on Wordpress 2.8.3

Please provide any additional information below.
The email verification function is this one:

function subscribe($email){
        $returnVal = array();
        /* switch to this If if you wish to support 
emails@localhost as a valid email address*/
        //if(!eregi("^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-
z0-9-]+)*(\.[a-z]{2,3})*$", $email)){
        if(!eregi("^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-
9-]+)*(\.[a-z]{2,4})$", $email)){
            $returnVal['result']=false;
            $returnVal['message']="Invalid email address.";
            return $returnVal;
        }

Original issue reported on code.google.com by dukessa....@gmail.com on 16 Aug 2009 at 4:15

[GoogleCodeExporter]

I've exactly the same problem..;
What I've to do to solve it ?
Thank you

Original comment by yves.dar...@gmail.com on 9 Oct 2009 at 8:19

[GoogleCodeExporter]

I'm having the same problem here as well - plugin v1.0 on WP 2.8.6.

Original comment by AthenaAn...@gmail.com on 13 Jan 2010 at 8:37