Can parents' learned traits be transmitted genetically?
Strictly speaking no. There are ideas about cultural inheritance though that seem relevant here: see http://www.ncbi.nlm.nih.gov/pubmed/11425279.  Cultural inheritance theory uses the plasticity of the human brain as the evidence for the underlying genetics of culture.  I.e. we aren't born with the ability to speak English because our parents learned it but we have an the underlying brain structure that is controlled by genetics to learn cultural traits.  It seems far more likely that the phenomenon you describe with holocaust survivors is more related to some environmental effects (from their parents) than anything genetic.  In the comments stress hormones in pregnant mothers were mentioned.  Any impact these have on the offspring are not truly "genetic", they're termed "maternal effects" in the evolution literature.  In fact most selection studies go to great lengths to control for them or eliminate them.  They aren't truly genetic because these traits would never get passed down to the grandoffspring of the original mother.