Stuck on an INSERT..

[KTBleeding]

I feel really dumb for asking this.

I'm still fairly new to coding in PHP so I'm a little confused here: Simply put, I'm trying to insert data into a table from a simple form but I can't get it to work. I've tried everything I can think of and I still don't understand.. Can anyone see an obvious error in the code?

Also, when sending the form an error popup tells me the following: (even when linking to member.php?u=$userinfo[userid])

This user has not registered and therefore does not have a profile to view.

PHP Code:

if ($_POST['do'] == 'insertnewcomment') {
    globalize($_POST, array('comment' => INT,'title' => STR_NOHTML));
    
    $DB_site->query("
    INSERT INTO ".TABLE_PREFIX."usercomment (userid,postedbyid,comment,title,dateline) 
    VALUES (".$userinfo[userid].",".$bbuserinfo[userid].",".mysql_escape_string($comment)."',".mysql_escape_string($title)."',".TIMENOW."')");

    $url = "member.php?$session[sessionurl]u=$userinfo[userid]";
    eval(print_standard_redirect('redirect_postthanks'));

} 


<form action="member.php" method="post">
	<input type="hidden" name="do" value="insertnewcomment" />
	<input type="hidden" name="userid" />
	<input type="hidden" name="postedbyid" />
	<input type="hidden" name="s" value="$session[sessionhash]" />
	<input class="bginput" type="text" name="title" size="45" maxlength="80" /><br />
	<input class="bginput" type="text" name="comment" size="45" maxlength="80" /><br />
		<input type="submit" class="button" value="Submit" accesskey="s" />
		</form>

Thanks,