Miami has two main problems. First, they are one dimensional on offense, and are wholly unable to pass the ball. While they can chew up large chunks rushing between the 20s, they can't get in the endzone because the defenses bunch up and its tough to punch it in when there are 11 guys in close.
And two: Miami has no pass rush. Joey and JT were supposed to be this great threat. Porter has 2 sacks, and Taylor has one, which is good. But they're not causing the QB to get rid of the ball quickly. The dbs can hold the receivers for a while, but at some point, there is just too much time.
You may have noticed yesterday that Sean Smith allowed a 47 yard pickup by the receiver he was covering. In his case, he was going for the pick, but the ball was SO perfectly thrown he missed it, and Jackson came down with it. That's the kind of fluky bad luck Miami is having this season.