diff --git a/stack/erp5/buildout.cfg b/stack/erp5/buildout.cfg
index 8f21ccb8f4d6009542ef04847433c04af09db627..19fe4c7fe00bc793eb03ec37b9a6e27e9285b3b3 100644
--- a/stack/erp5/buildout.cfg
+++ b/stack/erp5/buildout.cfg
@@ -294,7 +294,7 @@ md5sum = 9fff70e6958bccbb3d4982cb3611813f
 [template-cluster-zope]
 < = download-base
 filename = instance-cluster-zope.cfg.in
-md5sum = 019f306860857e8536f26aba32101b30
+md5sum = c5c13fb438aa2a4d9ce22880e16fc2cd
 
 [template-balancer]
 < = download-base
diff --git a/stack/erp5/instance-cluster-zope.cfg.in b/stack/erp5/instance-cluster-zope.cfg.in
index 0ec3cb40a744241b56f0a1e5ed5cce469e3ea095..95c798e47892840519e933bf211eb08277093253 100644
--- a/stack/erp5/instance-cluster-zope.cfg.in
+++ b/stack/erp5/instance-cluster-zope.cfg.in
@@ -1,5 +1,5 @@
 {% if slap_software_type == software_type -%}
-{% set use_ipv6 = parameter_dict.get('use-ipv6', False) -%}
+{% set use_ipv6 = slapparameter_dict.get('use-ipv6', False) -%}
 {% set next_port = slapparameter_dict['port-base'] -%}
 {% set site_id = slapparameter_dict['site-id'] -%}
 {% set storage_type = slapparameter_dict['zodb-storage-type'] -%}