diff --git a/nao_apps/nodes/nao_alife.py b/nao_apps/nodes/nao_alife.py
index bbab534..434997b 100755
--- a/nao_apps/nodes/nao_alife.py
+++ b/nao_apps/nodes/nao_alife.py
@@ -53,6 +53,8 @@ def __init__( self ):
 
         #Proxy to interface with LEDs
         self.proxy = self.get_proxy( "ALAutonomousLife" )
+        if self.proxy is None:
+            exit(1)
 
         # Register ROS services
         self.disabled_srv = rospy.Service("~disabled", Empty, self.disabled )
diff --git a/nao_apps/nodes/nao_behaviors.py b/nao_apps/nodes/nao_behaviors.py
index 1b2c01a..d3b3adc 100755
--- a/nao_apps/nodes/nao_behaviors.py
+++ b/nao_apps/nodes/nao_behaviors.py
@@ -60,6 +60,8 @@ def __init__( self ):
 
         #Proxy for listingBehaviors and stopping them
         self.behaviorProxy = self.get_proxy( "ALBehaviorManager" )
+        if self.behaviorProxy is None:
+            exit(1)
 
         # Register ROS services
         self.getInstalledBehaviorsService = rospy.Service(
diff --git a/nao_apps/nodes/nao_leds.py b/nao_apps/nodes/nao_leds.py
index 2214383..8e7ac59 100755
--- a/nao_apps/nodes/nao_leds.py
+++ b/nao_apps/nodes/nao_leds.py
@@ -58,6 +58,8 @@ def __init__( self ):
 
         #Proxy to interface with LEDs
         self.proxy = self.get_proxy( "ALLeds" )
+        if self.proxy is None:
+            exit(1)
 
         #Seed python's random number generator
         random.seed( rospy.Time.now().to_nsec() )