Well, this doesn't have much to do with the form not working, but your HTML isn't quite right.
Your form should be inside of the <body></body> tags, and you don't have a closing </html> tag.
The code for your page should look something like this:
HTML Code:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<title>Contact Form</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/mootools/1.3.0/mootools-yui-compressed.js"></script>
</head>
<body>
<form action="" method="POST" enctype="multipart/form-data">
<div align="center">
<br />Name*<br />
<input type="text" name="name" size="40" />
<br />Phone<br />
<input type="text" name="tel" size="40" />
<br />Your email*<br />
<input type="text" name="email" size="40" />
<br />Subject<br />
<input type="text" name="title" size="40" />
<br />Comment*<br />
<textarea rows="10" name="mess" cols="30"></textarea>
<br />File<br />
<input name="attachfile" type="file" size="28" />
<br />Pic<br />
<input name="attachimage" type="file" size="28" />
<br /><br /><input type="submit" value="Send" name="submit" />
</div>
</form>
* Can't be empty
</body>
</html>
However, regarding the form itself, it seems you don't have any action set for the form.
What page is the form information supposed to be submitted to? Is it submitting to the same page that the form is on, or is there an outside page with the code that will use the inputted information?