nfreq failed in task raman

That error is most likely from not specifying the necessary input for the polarizability calculations. For a Raman calculation you need to also give input for the polarizability calculation in the property block.

See the sample input in the documentation
http://nwchemgit.github.io/index.php/Release66:Properties#Raman

Note that damping is only needed if you are doing a resonance Raman calculation, and static polarizabilities are calculated by specifying a frequency of zero.