--- ./support_timer.module.orig_offset	2014-11-02 21:53:25.728463136 +0100
+++ ./support_timer.module	2014-11-02 21:55:34.016461913 +0100
@@ -487,7 +487,7 @@
 function support_timer_to_hours($time) {
   $time = explode(':', $time);
   $hours = (int)$time[0];
-  $minutes = round((int)$time[1] / 60, 2);
+  $minutes = (isset($time[1]) ? round((int)$time[1] / 60, 2) : 0);
   return $hours + $minutes;
 }