Which one plugin?

[Opserty]

<div style="margin:20px; margin-top:5px">
<div class="smallfont" style="margin-bottom:2px">$vbphrase[code]:</div>
<pre class="alt2" dir="ltr" style="
margin: 0px;
padding: $stylevar[cellpadding]px;
border: 1px inset;
width: $stylevar[codeblockwidth];
height: {$blockheight}px;
text-align: left;
overflow: auto">$code</pre>
<if condition="$show['member']">
JEŻELI CHCESZ ZOBACZYĆ LINKI MUSISZ SIE ZAREJESTROWAĆ!
</if>
</div>

$code is the variable that contains the data. That is what you need to hide...

For example:

<!-- Whatever HTML -->
<if condition="$show['member']">
    $code
<else />
    You need to register to see code....
</if>
<!-- More HTML if you need to -->