$bbuserinfo['userid'] is the userid of the person current browsing the site. You need to find another variable to compare this this two. (You may find a clue by looking at the template/phrase used to generate the link). Since this is custom script you'll have to find that variable yourself, I'll call it $yourvar for now.
Then in your template you would have:
Code:
<if condition="$bbuserinfo['userid'] != $yourvar['userid']">
DISPLAY LINK
</if>