Beginning to get there!
One of the most frequent reasons that pages don't immediately do what they are supposed to do, is because the paths to the other files they need to help them work are wrong. This can happen if you move a page without updating the links, and most often, because of the way your site is defined in Dreamweaver.
In your sites definition ( Dreamweaver menu > Site > Manage Sites > (select your site) Edit > 'Advanced' tab, under 'local info', make sure that your 'Links relative to' has 'Document' selected, and not 'Site Root'.
This ensures that whichever page you are viewing knows where the other pages are in relation to itself. At the moment it looks like your page is trying to find the files on your Mac hard-drive, because as far as it knows, that's where you have told it they are.
This will ensure that future pages will upload with the correct paths (!) hopefully. You should check this on any future Dreamweaver site you create.
In the mean time, you will need to edit the 'contactus.php' file to correct the faulty paths that have been created. Look for each of the following lines in your page:
<script src="file:///Macintosh HD/Users/chrisbritton/Desktop/eCart/Contact Form Solution Pack/ContactForm_GMC/SpryAssets/SpryValidationTextField.js" type="text/javascript"></script>
<script src="file:///Macintosh HD/Users/chrisbritton/Desktop/eCart/Contact Form Solution Pack/ContactForm_GMC/SpryAssets/SpryValidationTextarea.js" type="text/javascript"></script>
<link href="file:///Macintosh HD/Users/chrisbritton/Desktop/eCart/Contact Form Solution Pack/ContactForm_GMC/SpryAssets/SpryValidationTextField.css" rel="stylesheet" type="text/css" />
<link href="file:///Macintosh HD/Users/chrisbritton/Desktop/eCart/Contact Form Solution Pack/ContactForm_GMC/SpryAssets/SpryValidationTextarea.css" rel="stylesheet" type="text/css" />
<img src="file:///Macintosh HD/Users/chrisbritton/Desktop/eCart/Contact Form Solution Pack/ContactForm_GMC/WA_ValidationToolkit/WAVT_CaptchaSecurityImages.php?noisecolor=000000&bgcolor=ffffff&textcolor=000000&transparent=0&characters=5&width=200&height=40&font=Fonts/MOM_T___.TTF" alt="security code" /><br />
And remove everything after the first "(quote mark) up to and including ContactForm_GMC/ in each line.
So for instance, the first of these would now look like:
<script src="SpryAssets/SpryValidationTextField.js" type="text/javascript"></script>
When you've done that, upload the page and see what you get. If all is OK, we should be able to help with the site integration.
It is a simple process (one or two steps) to have the form on a page as you describe. Do you want the page with the form on it to have the flv video on it (to the right of the content)?