Permission denied

I'm using this package in Plone 4.3.6. When I run

```
bin/plonectl fg
```

I got the following error:

```
zope.configuration.xmlconfig.ZopeXMLConfigurationError: File "/usr/local/Plone-4.3.6-standalone/zinstance/parts/instance/etc/site.zcml", line 12.2-12.39
ZopeXMLConfigurationError: File "/usr/local/Plone-4.3.6-standalone/buildout-cache/eggs/Products.CMFPlone-4.3.6-py2.7.egg/Products/CMFPlone/meta.zcml", line 42.4-46.10
IOError: [Errno 13] Permission denied: '/usr/local/Plone-4.3.6-standalone/buildout-cache/eggs/bibliograph.rendering-1.0.2-py2.7.egg/EGG-INFO/entry_points.txt'
```

The file in question has the following permissions

```
-rw------- 1 plone_buildout plone_group 25 Jun 26 21:43 entry_points.txt
```