Thats because you've posted as though asking for help with vb3 and that postbit is from vb4!
Here's the line you want
HTML Code:
<dt>{vb:rawphrase posts}</dt><dd>{vb:raw post.posts}</dd>
and wrap it like this
HTML Code:
<vb:if condition="$post['userid'] == '6'"><dt>{vb:rawphrase posts}</dt><dd>??</dd><vb:else /><dt>{vb:rawphrase posts}</dt><dd>{vb:raw post.posts}</dd><vb:/if>