diff -up hplip-3.13.3/doctor.py.sts hplip-3.13.3/doctor.py
--- hplip-3.13.3/doctor.py.sts	2013-03-11 12:01:48.000000000 +0100
+++ hplip-3.13.3/doctor.py	2013-03-11 12:25:16.944767786 +0100
@@ -133,7 +133,7 @@ def install_plugin(core):
         cmd=utils.which('hp-plugin',True)
         if cmd:
             cmd = core.passwordObj.getAuthCmd() %append_options(cmd)
-            os_utils.execute(cmd)
+            sts = os_utils.execute(cmd)
             if sts == 0:
                 return True
         else: