[web2py] exception when trying to run w2p_run command!

Hello, I'm new to web2py, I installed the stable version on my system and ran w2p_run but something goes wrong: jorge [~] ~> w2p_run WARNING:root:Unable to import plural rules: No module named plural_rules Traceback (most recent call last): File "/usr/bin/w2p_run", line 5, in pkg_resource

[web2py] running in troubles with w2p_run

Hello, I have this problem when I want to start web2py with w2p_run command: jorge [~] ~> w2p_run WARNING:root:Unable to import plural rules: No module named plural_rules Traceback (most recent call last): File "/usr/bin/w2p_run", line 5, in pkg_resources.run_script( 'web2py==2.5.1-stable-