I would suggest to Google "samsung wave shutting off when using..." and describe the symptoms. The returned search results usually have more than one link to forums where other users described similar problems. I assumed it was the dialer because of what you mentioned in the first post; now, that you mentioned other apps as well, not sure it's the dialer app anymore, but it could be some corrupted system files in the ROM.
You could try to see if the problem occurs with another SIM card; you can borrow one or go to the carrier's rep and try it there.