I've just uploaded my site, but using a contact form I receive following message error:

Warning: mail() [function.mail]: Mail() functionality if not on by default; please purchase this option by contacting zymic.com in /www/zxq.net/p/u/c/pucfilantiga/htdocs/documents/htmlMimeMail.php on line 684
sending mail failed.

What should I to do?

Mail can be enabled for a one off $10 charge, pop onto http://livechat.zymic.com/hosting and we'll give you further instructions.