For other newbs out there this is what I finally did:
Added to my php-direct-eval POST form:
PHP Code:
<input type="hidden" name="nocache" value="yes" />
then added to the file /forum/includes/init.php under the init_stratup (near line 330 in unmodded vb 4.1.3)
PHP Code:
if ($_POST['nocache']=='yes')
{
$vbulletin->options['nocache'] = 1;
}
Now the code works with caching enabled and one just needs to remember this fix on future vb updates