Rava said: If a person sees suffering coming upon him, he should examine his actions. If he examined and did not find [any defects], he should attribute [the suffering] to neglect of Torah study. (Brachot 5a)
How can a person possibly examine his actions and not find anything that needs fixing? As Kohelet 7:20 says, "there is no person on earth who does good and never sins"!
And furthermore, what's so important about Torah study that even a perfectly behaving person can be punished for not doing enough of it?
I could try answering the second question with my previous post, but I would prefer to try answering both questions at once.
If you examine your actions and find nothing wrong, it is probably not the case that you are a perfect person. It's more likely that you did something wrong, but don't realize it. Luckily enough, this situation can be remedied by learning what you did wrong. If you don't know basic halacha, you can study it. If you are too spiritually lax or inconsiderate of other people, you can study mussar, philosophy or Tanach to impress upon yourself the proper attitude by which to go about your life. Most of us could use a little of both types of study.
But if you had the opportunity to learn, and passed it up, and ended up violating laws you didn't know about or appreciate, then it is really your fault for choosing not to learn in the first place. Such an person, one who does things wrong but thinks he does nothing wrong because of his ignorance, really should blame the punishment he gets on neglect of Torah study.