I got no matches at all with miyagawa's original line:

 next unless m@GET /default\.ida\?[XN]+@;
[download]

After I changed this to:

 next unless m@GET /default\.ida ?[XN]+@;
[download]

I get matches.

I set $to to my email address for testing purposes. Each time I run the script, I get a blank message (no body). $message isn't getting setup properly. If I turn on warnings, I get lots of "Use of uninitialized value in hash element..."