Rudder

When installing current nightly on centos 4.1, i have the following error

==> centos41_server:
==> centos41_server: *****************************************************************************************
==> centos41_server: INFO: Now run on your root server:                                                            
==> centos41_server: INFO:   '/opt/rudder/bin/rudder-node-to-relay eb26dcdf-6287-4d73-9694-5ca51e513190
==> centos41_server: INFO: Please look at the documentation for details (Section 'Relay servers')          
==> centos41_server: *******************************************************************i*********************
 Installing : tzdata-java-2017b-1.el6.noarch                             34/48
==> centos41_server:  
 Installing : freetype-2.3.11-17.el6.x86_64                              35/48
==> centos41_server:  
 Installing : 1:java-1.8.0-openjdk-headless-1.8.0.144-0.b01.el6_9.x86_   36/48
==> centos41_server:  
 Installing : 1398866025:rudder-jetty-4.1.8.rc1.git201710190307-1.EL.6   37/48
==> centos41_server:  
==> centos41_server: Stopping Jetty: OK
==> centos41_server: Traceback (most recent call last):
==> centos41_server:   File "/opt/rudder/bin/rudder-pkg", line 41, in <module>
==> centos41_server:     import argparse
==> centos41_server: ImportError: No module named argparse
==> centos41_server: error: %pre(rudder-webapp-1398866025:4.1.8.rc1.git201710190307-1.EL.6.noarch) scriptlet failed, exit status 1
==> centos41_server: Error in PREIN scriptlet in rpm package 1398866025:rudder-webapp-4.1.8.rc1.git201710190307-1.EL.6.noarch
==> centos41_server: error:   install: %pre scriptlet failed (2), skipping rudder-webapp-1398866025:4.1.8.rc1.git201710190307-1.EL.6
 Installing : 1398866025:rudder-inventory-endpoint-4.1.8.rc1.git201710   39/48
==> centos41_server:  

webapp is not functionnal afterward