diff --git a/Shorewall-perl/Shorewall/Chains.pm b/Shorewall-perl/Shorewall/Chains.pm
index 7cf3527df..721dc540e 100644
--- a/Shorewall-perl/Shorewall/Chains.pm
+++ b/Shorewall-perl/Shorewall/Chains.pm
@@ -257,7 +257,7 @@ sub push_cmd_mode( $ ) {
     $_[0]->{cmdcount}++;
 }
 
-sub pop_cmd_mode() {
+sub pop_cmd_mode( $ ) {
     fatal_error "Internal error in pop_cmd_mode()" if --$_[0]->{cmdcount} < 0;
 }
 
diff --git a/Shorewall-perl/Shorewall/Nat.pm b/Shorewall-perl/Shorewall/Nat.pm
index fe6a6cad2..026f208a7 100644
--- a/Shorewall-perl/Shorewall/Nat.pm
+++ b/Shorewall-perl/Shorewall/Nat.pm
@@ -28,6 +28,7 @@ require Exporter;
 use Shorewall::Common;
 use Shorewall::Config;
 use Shorewall::Zones;
+use Shorewall::Interfaces;
 use Shorewall::Chains;
 use Shorewall::IPAddrs;