diff --git a/cleaner.css b/cleaner.css
index 4348cab..e17c837 100644
--- a/cleaner.css
+++ b/cleaner.css
@@ -7,16 +7,23 @@
   margin: 0.5em 0 0.5em 0;
   padding: 6px 0;
 }
+
 #cleaner-settings-form .description {
   clear: both;
   margin: 3px 0 0 1.5em;
   padding: 0;
 }
+
 #cleaner-settings-form .form-type-radio {
   margin: 0 0 0 1em;
   padding: 0;
 }
+
 #cleaner-settings-form table.cleaner-cache-tables {
   width: auto;
   margin-left: 1em;
 }
+
+#cleaner-settings-form .disabled {
+  color: #ff0000;
+}
diff --git a/cleaner.module b/cleaner.module
index bc627b4..75151d1 100644
--- a/cleaner.module
+++ b/cleaner.module
@@ -107,14 +107,20 @@ function cleaner_cleaner_settings() {
     '#description'    => t('A comma separated list of table names which also needs to be cleared.'),
   );
 
-  $form['cleaner_empty_watchdog'] = array(
-    '#type'           => 'radios',
-    '#options'        => $yes_no,
-    '#title'          => t('Clean up Watchdog'),
-    '#default_value'  => variable_get('cleaner_empty_watchdog', 0),
-    '#description'    => t('There is a standard setting for controlling Watchdog contents. This is more useful for test sites.'),
-    '#attributes'     => $inline,
-  );
+  if (module_exists('dblog')) {
+    $form['cleaner_empty_watchdog'] = array(
+      '#type' => 'radios',
+      '#options' => $yes_no,
+      '#title' => t('Clean up Watchdog'),
+      '#default_value' => variable_get('cleaner_empty_watchdog', 0),
+      '#description' => t('There is a standard setting for controlling Watchdog contents. This is more useful for test sites.'),
+      '#attributes' => $inline,
+      );
+  }
+  else {
+    // DBLog module not active, so make sure we don't try to clear it.
+    variable_set('cleaner_empty_watchdog', 0);
+  }
 
   $cookie = session_get_cookie_params();
   $select = db_select('sessions', 's')
@@ -140,6 +146,10 @@ function cleaner_cleaner_settings() {
     '#description'    => t('The CSS directory can become full with stale and outdated cache files.  This will delete all CSS cache files but the latest.'),
     '#attributes'     => $inline,
   );
+  if (variable_get('preprocess_css', 0) == 0) {
+    $form['cleaner_clean_cssdir']['#description'] .= ' <span class="disabled">' 
+      . t('This feature is disabled.') . '</span>';
+  }
 
   $form['cleaner_clean_jsdir'] = array(
     '#type'           => 'radios',
@@ -149,6 +159,10 @@ function cleaner_cleaner_settings() {
     '#description'    => t('The JS directory can become full with stale and outdated cache files.  This will delete all JS cache files but the latest.'),
     '#attributes'     => $inline,
   );
+  if (variable_get('preprocess_js', 0) == 0) {
+    $form['cleaner_clean_jsdir']['#description'] .= ' <span class="disabled">' 
+      . t('This feature is disabled.') . '</span>';
+  }
 
   // We can only offer OPTIMIZE to MySQL users.
   if (db_driver() == 'mysql') {