diff --git a/libtransmission/natpmp.c b/libtransmission/natpmp.c
index c18cfe2a6..529f35078 100644
--- a/libtransmission/natpmp.c
+++ b/libtransmission/natpmp.c
@@ -21,6 +21,7 @@
 #include <arpa/inet.h> /* inet_ntoa */
 #endif
 
+#define ENABLE_STRNATPMPERR
 #include <libnatpmp/natpmp.h>
 
 #include "transmission.h"
@@ -69,7 +70,9 @@ logVal( const char * func, int ret )
     if( ret >= 0 )
         tr_ninf( getKey(), _( "%s succeeded (%d)" ), func, ret );
     else
-        tr_ndbg( getKey(), "%s failed (%d): %s (%d)", func, ret, tr_strerror(errno), errno );
+        tr_ndbg( getKey(), "%s failed.  natpmp returned %d (%s); errno is %d (%s)",
+                 func, ret, strnatpmperr(ret), errno, tr_strerror(errno) );
+
 }
 
 struct tr_natpmp*
diff --git a/third-party/libnatpmp/Makefile.am b/third-party/libnatpmp/Makefile.am
index 3fca7d53c..923ab169d 100644
--- a/third-party/libnatpmp/Makefile.am
+++ b/third-party/libnatpmp/Makefile.am
@@ -1,5 +1,7 @@
 noinst_LIBRARIES = libnatpmp.a
 
+AM_CPPFLAGS = -DENABLE_STRNATPMPERR
+
 libnatpmp_a_SOURCES = \
     getgateway.c \
     natpmp.c