Tinymce deletes tags when output in textarea

I have made a own litle cms with the tinymce. When inserting plain text in pre tags the code gets outputed the right way on the website but when i update the editor the html tags gets removed.

Tinymce setup

<script type="text/javascript">
tinyMCE.init({

    selector: "textarea.editme",
   width : "60.5%",
   resize: false,
preformatted : true,
menubar:false,

});
</script>

Tinymce Editor

<textarea name="content"><?php echo $data['course_content'];?>  </textarea><br />

I echo out the content from the Database here but as I said the html tags gets deleted in the textarea.All other text is showed.