No, the form does't need an action.
<form action="" method="post" name="emailContact" id="emailContact" onsubmit="">
The form should (in theory) forward to your 'thankyou.php' page on successful submission.
Make sure that all of the solution pack files have been uploaded to your server correctly.
What settings did you put for ' $WAGLOBAL_Email_Server = "" ; ' in your WA_Globals.php file? Normally this works if it is left blank, but it might be worth checking with your hosting company if emails can be sent using php mail. They might have specific instructions.
If necessary upload a clean version of the CFSP to a temporary location without having done any modification other than to the WA_globals file, and see if the contactus.php form will send.
Although sending the form should have sent you to the 'thankyou.php' page, there's a possibility that an email was sent, so make sure that the email address you entered in the WA_globals file was entered correctly (maybe try another address if you have one) and that your mail account (and any forwarders you may use) isn't filtering it as spam.
Try this first, and post back.