我在我的系统上下载并安装了 web2py 2.5.1 stable，并阅读了我试图通过运行来启动应用程序的书，w2p_run但我遇到了这个异常：
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 <module>
pkg_resources.run_script('web2py==2.5.1-stable-timestamp.2013.06.06.15.39.19', 'w2p_run')
File "/usr/lib/python2.7/site-packages/pkg_resources.py", line 505, in run_script
self.require(requires)[0].run_script(script_name, ns)
File "/usr/lib/python2.7/site-packages/pkg_resources.py", line 1245, in run_script
execfile(script_filename, namespace, namespace)
File "/usr/lib/python2.7/site-packages/web2py-2.5.1_stable_timestamp.2013.06.06.15.39.19-py2.7.egg/EGG-INFO/scripts/w2p_run", line 17, in <module>
import gluon.widget
File "/usr/lib/python2.7/site-packages/web2py-2.5.1_stable_timestamp.2013.06.06.15.39.19-py2.7.egg/gluon/widget.py", line 25, in <module>
import main
File "/usr/lib/python2.7/site-packages/web2py-2.5.1_stable_timestamp.2013.06.06.15.39.19-py2.7.egg/gluon/main.py", line 120, in <module>
raise RuntimeError("Cannot determine web2py version")
RuntimeError: Cannot determine web2py version
jorge [~] ~>
我真的很想开始使用 web2py，所以，有什么帮助吗？:(