ImportError: No module named resources

Plone 4.3.6
collective.documentviewer: 5.0.0

Hello, I'm trying to use the latest version of the product, however this error is displayed when I try to start the Plone instance

```
ZopeXMLConfigurationError: File "/home/caroline/Plone/buildout-cache/eggs/collective.documentviewer-5.0.0-py2.7.egg/collective/documentviewer/configure.zcml", line 66.2-66.32
ZopeXMLConfigurationError: File "/home/caroline/Plone/buildout-cache/eggs/collective.documentviewer-5.0.0-py2.7.egg/collective/documentviewer/browser/configure.zcml", line 11.2-17.34
ImportError: No module named resources

```

Before that I tried to use version collective.documentviewer 4.1.0 and started the instance correctly, however, when trying to convert the file a conversion error was displayed.

```
Traceback (most recent call last):
File "/home/caroline/Plone/buildout-cache/eggs/collective.documentviewer-4.1.0-py2.7.egg/collective/documentviewer/convert.py", line 595, in __call__
pages = self.run_conversion()
File "/home/caroline/Plone/buildout-cache/eggs/collective.documentviewer-4.1.0-py2.7.egg/collective/documentviewer/convert.py", line 426, in run_conversion
return docsplit.convert(self.storage_dir, **args)
AttributeError: 'NoneType' object has no attribute 'convert'
```

P.S. The file I tried to convert was a .PDF