FATAL: NameError: python_pipvirtualenv (python::virtualenv line 23) had an error: NameError: Cannot find a resource for converge_by on centos version 6.3
The solution to this problem occured to be trivial: converge_by resource has been introduced quite recently in a newer version of Chef. Therefore a simple update to Chef solved this problem.
sudo gem update chef ohai --no-ri --no-rdoc
And the error is gone!