Well to start with if you only want registered users to see it it needs to be moved up a bit.
PHP Code
{if $user_list}
<a href="{ubb url="ubb=showmembers"}">{$lang.USER_LIST}</a> &nbsp;&nbsp;&nbsp;
{/if}

{* LR:Mod - reason for modification - self search link *}
<a href="{ubb url="ubb=selfsearch"}">{$lang.SELF_SEARCH}</a>

Move it above the (/if) to:

PHP Code
{if $user_list}
<a href="{ubb url="ubb=showmembers"}">{$lang.USER_LIST}</a> &nbsp;&nbsp;&nbsp;
{* LR:Mod - reason for modification - self search link *}
<a href="{ubb url="ubb=selfsearch"}">{$lang.SELF_SEARCH}</a>
{/if}

Why is it blank could be several items.
Such as does the language file key self_search have any text in it so at least something shows.
Should have been added to the generic.php file
Key: SELF_SEARCH
String: Self Search.
Then the question is does the actual script work.

Blue Man Group
There is no such thing as stupid questions. Just stupid answers