diff --git a/html/includes/authenticate.inc.php b/html/includes/authenticate.inc.php
index 3422b826a3..4d7d7c1814 100644
--- a/html/includes/authenticate.inc.php
+++ b/html/includes/authenticate.inc.php
@@ -3,6 +3,22 @@
 @ini_set("session.gc_maxlifetime","0"); 
 
 session_start();
+
+// Preflight checks
+if(!is_dir($config['rrd_dir']))
+  echo "<div class='errorbox'>RRD Log Directory is missing ({$config['rrd_dir']}).  Graphing may fail.</div>";
+
+if(!is_writable($config['rrd_dir']))
+  echo "<div class='errorbox'>RRD Log Directory is not writable ({$config['rrd_dir']}).  Graphing may fail.</div>";
+
+if(!is_dir($config['tmp_dir']))
+  echo "<div class='errorbox'>Temp Directory is missing ({$config['tmp_dir']}).  Graphing may fail.</div>";
+
+if(!is_writable($config['tmp_dir']))
+  echo "<div class='errorbox'>Temp Directory is not writable ({$config['tmp_dir']}).  Graphing may fail.</div>";
+
+
+
 if(isset($_GET['logout']) && $_SESSION['authenticated']) {
   mysql_query("INSERT INTO authlog (`user`,`address`,`result`) VALUES ('" . $_SESSION['username'] . "', '".$_SERVER["REMOTE_ADDR"]."', 'logged out')");
   unset($_SESSION);
@@ -34,8 +50,7 @@ if (file_exists('includes/authentication/' . $config['auth_mechanism'] . '.inc.p
 }
 else
 {
-  # FIXME use standard error message box?
-  echo "ERROR: no valid auth_mechanism defined.";
+  echo "<div class='errorbox'>ERROR: no valid auth_mechanism defined</div>";
   exit();
 }
 
diff --git a/html/includes/functions.inc.php b/html/includes/functions.inc.php
index 068fc7e5fd..9437abdfa4 100644
--- a/html/includes/functions.inc.php
+++ b/html/includes/functions.inc.php
@@ -212,10 +212,10 @@ function generate_port_thumbnail($args)
     echo $output;
 }
 
-function print_optionbar_start ($height = 20, $width = 0) 
+function print_optionbar_start ($height = 20, $width = 0, $marginbottom = 5) 
 {
   echo("
-    <div style='text-align: center; margin-top: 0px; margin-bottom: 0px; " . ($width ? 'max-width: ' . $width . (strstr($width,'%') ? '' : 'px') . '; ' : '') . "'>
+    <div style='text-align: center; margin-top: 0px; margin-bottom: ".$marginbottom."px; " . ($width ? 'max-width: ' . $width . (strstr($width,'%') ? '' : 'px') . '; ' : '') . "'>
     <b class='rounded'>
     <b class='rounded1'><b></b></b>
     <b class='rounded2'><b></b></b>
diff --git a/html/includes/graphs/diskio_ops.inc.php b/html/includes/graphs/diskio_ops.inc.php
index 158c806843..04a8d69969 100644
--- a/html/includes/graphs/diskio_ops.inc.php
+++ b/html/includes/graphs/diskio_ops.inc.php
@@ -22,7 +22,7 @@ $colour_area_out_max = "FF9966";
 
 $graph_max = 1;
 
-$unit_text = "Operations";
+$unit_text = "Ops/s";
 
 include("generic_duplex.inc.php");