diff --git a/core/net/rime/collect.c b/core/net/rime/collect.c
index c59345972..1c19dfe19 100644
--- a/core/net/rime/collect.c
+++ b/core/net/rime/collect.c
@@ -33,7 +33,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * $Id: collect.c,v 1.37 2010/03/09 13:21:28 adamdunkels Exp $
+ * $Id: collect.c,v 1.38 2010/03/12 15:21:14 dak664 Exp $
  */
 
 /**
@@ -628,7 +628,7 @@ collect_open(struct collect_conn *tc, uint16_t channels,
   neighbor_discovery_open(&tc->neighbor_discovery_conn, channels,
 			  CLOCK_SECOND * 8,
 			  CLOCK_SECOND * 32,
-			  (CLOCK_SECOND * 600UL),
+			  (unsigned)(CLOCK_SECOND * 600UL),
 			  &neighbor_discovery_callbacks);
   neighbor_discovery_start(&tc->neighbor_discovery_conn, tc->rtmetric);
 #else /* !COLLECT_ANNOUNCEMENTS */