diff --git a/system/sysctl b/system/sysctl
index 59b92eb6f48..3541a45aee9 100644
--- a/system/sysctl
+++ b/system/sysctl
@@ -181,7 +181,7 @@ class SysctlModule(object):
         thiscmd = "%s -w %s=%s" % (self.sysctl_cmd, token, value)
         rc,out,err = self.module.run_command(thiscmd)
         if rc != 0:
-            self.module.fail_json(msg='setting %s failed: %s' (token, out + err))
+            self.module.fail_json(msg='setting %s failed: %s' % (token, out + err))
         else:
             return rc