It will be great if you told him how to remove it instead of saying where at.
Go to Style Manager>Skin Name>Edit Template>Postbit Template>Postbit(Double Click it)
Find
<if condition="$post['joindate']"><div>$vbphrase[join_date]: $post[joindate]</div></if>
<if condition="$post['usertitle']"><div class="smallfont">$post[usertitle]</div></if>
Than go to Postbit Legacy and find
<div align="center"><if condition="$post['usertitle']"></if></div>
<if condition="$post['usertitle']"><div class="smallfont">
<div align="center">$post[usertitle]</div>
</div></if>
<if condition="$post['joindate']"><div>$vbphrase[join_date]: $post[joindate]</div></if>
Just delete those codes.
Hope that helps.