qgis - PyQGIS in standalone script, vector loading error

I am trying to use the QGIS functions in a stand alone Python script. I'm running Mountain Lion OS, 2.7 Python & the QQGISis 2.0.1 Dufour.

My main problem is that I cannot get started - I cannot load a simple shapefile in order to buffer it. After searching the online resources quite a bit, I actually found that many people had a problem with setting the prefix path, so I ran the QgsApplication.showSettings() to identify it.

The code I'm running now is:

 QgsApplication.setPrefixPath("/Applications/QGIS.app/Contents", True)  
    QgsApplication.initQgis()          
    print QgsApplication.showSettings()        
    #Loading a Layer  
    layer = QgsVectorLayer('/path/to/shapefile_folder/test.shp', 'test', 'ogr')
    if not layer.isValid():  

        print "The layer failed to load."          
    #finally I d like to apply a buffer, sth like that maybe? 
    buffer_Shp = layer.buffer(10, 5) 

Here is the result I get:

 Application state:
    QGIS_PREFIX_PATH env var:       
    Prefix:     /Applications/QGIS.app/Contents
    Plugin Path:        /Applications/QGIS.app/Contents/../PlugIns/qgis
    Package Data Path:  /Applications/QGIS.app/Contents/../Resources

    Active Theme Name:  
    Active Theme Path:  :/images/themes//
    Default Theme Path: :/images/themes/default/
    SVG Search Paths:   /Applications/QGIS.app/Contents/../Resources/svg/
    User DB Path:   /Applications/QGIS.app/Contents/../Resources/resources/qgis.db

"The Layer Failed to load" (obviously)

bash_profile (in case that sth is wrong there)

 /# Setting PATH for Python 2.7
    /# The orginal version is saved in .bash_profile.pysave

    /######export PYTHONPATH=/usr/local/lib/python:$PYTHONPATH
    export PATH=/usr/local/bin:$PATH
    export PATH=/usr/local/share/python:$PATH    
    /#adding Qgis libs  
    export DYLD_LIBRARY_PATH=/Applications/QGIS.app/Contents/MacOS/lib/:/Applications/QGIS.app/Contents/Frameworks/
    export PYTHONPATH=/Applications/QGIS.app/Contents/Resources/python/
    export PATH=/Library/Frameworks/GDAL.framework/Programs:$PATH
    /# Added by Canopy installer on 2013-10-06
    /# VIRTUAL_ENV_DISABLE_PROMPT can be set to '' to make bashprompt show that Canopy is active, otherwise 1
    /# VIRTUAL_ENV_DISABLE_PROMPT=1 source /Users/george/Library/Enthought/Canopy_64bit/User/bin/activate

What the heck am I missing?