diff --git a/sites/all/modules/openlayers_proximity/views/openlayers_proximity_handler_field.inc b/sites/all/modules/openlayers_proximity/views/openlayers_proximity_handler_field.inc
index 284f256..cc4c56e 100644
--- a/sites/all/modules/openlayers_proximity/views/openlayers_proximity_handler_field.inc
+++ b/sites/all/modules/openlayers_proximity/views/openlayers_proximity_handler_field.inc
@@ -56,7 +56,7 @@ class openlayers_proximity_handler_field extends views_handler_field_numeric {
       $value = number_format($value, 0, '', $this->options['separator']);
       if ($remainder) {
         // The substr may not be locale safe.
-        $value .= $this->options['decimal'] . substr($remainder, 2);
+        $value .= $this->options['decimal'] . drupal_substr($remainder, 2);
       }
     }
 
diff --git a/sites/all/modules/openlayers_proximity/views/openlayers_proximity_handler_filter.inc b/sites/all/modules/openlayers_proximity/views/openlayers_proximity_handler_filter.inc
index 53424e7..8188bfa 100644
--- a/sites/all/modules/openlayers_proximity/views/openlayers_proximity_handler_filter.inc
+++ b/sites/all/modules/openlayers_proximity/views/openlayers_proximity_handler_filter.inc
@@ -396,7 +396,7 @@ class openlayers_proximity_handler_filter extends views_handler_filter_float {
     if ($this->filter_item_is_exposed('node') && $this->options['location_as'] == 'node' || arg(2) == 'views') {
       $results = db_query("SELECT n.title, n.nid FROM {openlayers_proximity} op LEFT JOIN {node} n ON n.nid = op.nid WHERE n.status = 1 ORDER BY n.title ASC");
       while ($row = db_fetch_object($results)) {
-        $options[$row->nid] = check_plain(substr($row->title, 0, 40));
+        $options[$row->nid] = check_plain(drupal_substr($row->title, 0, 40));
       }
     }
     return $options;