Email form created in Acrobat 9, custom subject line and content

Question

I'm revisiting a form I created about a year back, and I can't remember how I got a javascript to work.
What I want is for the user to click on an "Email" button, which will open their email program and create a new message, with the subject line filled out from one of the form fields, and then will have specified text in the body, as well as attaching the document and sending it to multiple email addresses.
I have a javascript that I thought worked, but I keep getting error messages on it when I try to test it out.
The script I'm currently trying to make work is:
// This is the form return e-mail. Its hardcoded
// so that the form is always returned to the same address
// Change address on your form
var cToAddr = "[email protected]; [email protected]";
// First, get the client CC e-mail address
var cCCAddr = this.getField("Teacheremail").value;
// Set the subject and body text for the e-mail message
var cSubLine = this.getField("CourseNumber").value + " corrections form submitted by "
+ this.getField("TeacherName").value;
var cBody = "\nThank you for submitting your form.\n" +
               "Save the mail attachment for your own records.\n" +
               "Do NOT worry if the form appears blank in your email message.";
// Send the form data as an PDF attachment on an e-mail
this.mailDoc({bUI: true, cTo: cToAddr, cCc: cCCAddr,
  cSubject: cSubLine, cMsg: cBody});
What am I doing wrong?

Answer 1

forgot to add
This is the error message, but there is a correct email listed in the Teacheremail field, so I don't know why it says it's "null."
this.getField("Teacheremail") is null
7:AcroForm:Email:Annot1:MouseUp:Action1
TypeError: this.getField("Teacheremail") is null
7:AcroForm:Email:Annot1:MouseUp:Action1