P.L.
I think your actions depend on your son's age. When kids are young (sometimes through teens) and not able to express their feelings in words - they get frustrated and act out. Usually a phase - yet you need to respond to each situation - reminding him of the proper response - and maybe helping him express his feelings.
It may sound funny - but when my kids were so frustrated they couldn't express themselves - I would say things like "You seem angry" "I would be so mad if this happened to me" "sometimes things make me so sad / mad" - - and just give them the words that maybe they would use if they could think of them themselves.
Also - discussing what proper behavior would be - if he gets mad or disappointed or really angry - - give him some good ideas. I had my kids breath - 3 big breaths. Anything you want to give as an idea - maybe stamping a foot.... Also - watch how you and your husband respond when frustrated - - he is most proabably watching you and will pick up your good (or bad) habits.
Also - agree or not - I'd watch SuperNanny. My kids are 16 & 19 and I really think she gives great advice. Many of the things she promotes are things we did as my kids grew up.
Good luck