--- a/src/devices/wifi/mac-low.cc	Thu Jun 12 11:06:56 2008 -0700
+++ b/src/devices/wifi/mac-low.cc	Thu Jun 12 11:14:54 2008 -0700
@@ -414,7 +414,7 @@
 }
 
 void
-MacLow::ReceiveError (Ptr<Packet> packet, double rxSnr)
+MacLow::ReceiveError (Ptr<const Packet> packet, double rxSnr)
 {
   NS_LOG_FUNCTION (this << packet << rxSnr);
   MY_DEBUG ("rx failed ");