The fmail.pl script requires an email field to use as the "From" address for sending the results. It also requires 4 hidden fields which are recipient, subject, required, and redirect The syntax is below:

<input type="hidden" name="recipient" value="yourname@your-actual-domain.com">
<input type="hidden" name="subject" value="Inquiry Form">
<input type="hidden" name="redirect" value="http://your-actual-domain.com/thankyou.html">

<input type="hidden" name="required" value="email">

In designing your form, make sure that the field where you ask for their email address is named "email" (all lower case with no dashes). The syntax is:
<input name="email" value size="50">
 

Click here, to view the form mail script syntax.

If the form is generating an "Internal Server Error", the most likely causes are:
1. The form field requesting the email address is not named "email" (all lower case).
2. The recipient address that you specified is not on your domain.
3. The recipient address that you specified is an email address that does not exist on your domain.
4. The email field is not set as required, and that field is not filled in when the form is being submitted.

The way around this is to not have direct links to email addresses on your site but instead have links to forms pages where your shoppers can submit their queries. Secondly, on the forms pages that you create, omit the line below:
<input type="hidden" name="recipient" value="yourname@your-actual-domain.com">
When you omit the recipient field on your page, the fmail.pl script will not know where to send the form results. So you will need to:

1.  Download (in ASCII mode not binary mode) the fmail.pl script from your site using FTP software. 
2. Open the fmail.pl script on your local computer using something like WordPad.
3. Find the line below: (it will of course show your actual domain name not the your-actual-domain.com)
 @allow_mail_to = qw(your-actual-domain.com localhost);
4. Change that line to:
 @allow_mail_to = qw(secretemailaddress@your-actual-domain.com your-actual-domain.com localhost);
You are leaving the your domain name in the field but before it, you are adding a default email address that the fmail.pl script will use if your page does not pass it a value for the recipient.
5. Re-upload (in ASCII mode not binary mode)  the fmail.pl script to the server, into your cgi-bin directory.
6. Now test your form.