Mail daemons can be real sticklers about their headers. Have you set up mime headers for the mail that gets sent? Here's some code that works for me, slightly altered for you. Hope it works!
Inger
-- begin code --
$you = "$your_email";
$client = "$your_client's_email";
$headers .= "MIME-Version: 1.0\r\n";
$headers .= "Content-type: text/html; charset=iso-8859-1\r\n";
$headers .= "From: $your_form_email";
$headers .= "Cc: $client\r\n";
$headers .= "X-MSMail-Priority: Medium\r\n";
$headers .= "X-Mailer: PHP\n";
$headers .= "X-Priority: 2\n";
$subject = "Form Submission";
$message = "conglomeration of all of your form fields";
mail($you, $subject, $message, $headers) or die ("couldn't send mail!"

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