That's not the complete HTML code. Looking at the source, apparently you have:
<input type='hidden' value='http://erasmus-plus.ro/wp-content/plugins/form-maker' id='form_plugins_url' />
In line 41. That's "displayable" code, so I think it's making that the head part closes and opening the <body> implicitly, and hence complaining when it gets to your explicit tag.
I guess that some stray plugin is misbehaving using wp_head to insert that into your . Try disabling your plugins one by one and you'll probably find the culprit. Probably something related to forms?