zMario and Usy, Sureshot has tried to get you two to understand, and he's failing. Let me put it in simple terms i would understand.
Mugabe - Bad man! Has been for years.
Zimbabwe - In a terrible way due to the Mugabe
Zimbabwe Cricket - Unfortunate bystanders
Basically, most of the world want to get Mugabe out of power. Mugabe it seems is going no where, and hasnt gone anywhere in many years. Due to this, all countries are slowly cutting ties with Zimbabwe to mount pressure on Mugabe. By doing this everything in Zimbabwe is effected, from money, to jobs to unfortunately Cricket.
The Cricket side of things is extremely unlucky, but basically the ECB have gone to the English Government, and asked could the Zimbabwe team be "blocked," from coming into the country. This way, the ECB don't get too heavily fined as its a Government matter, this didnt really go ahead BUT an agreement was done between the ECB and Zimbabwe Cricket (I'm guessing the ICC where heavily involved).
This means the Mugabe WONT be recieving a penny from the UK, which is the message a lot of countries are trying to send out. Its all about mounting pressure on Mugabe.
Now let me finish with, Zimbabwe cricket are innocent, but are part of a much bigger problem. As Sureshot said, there have been players like Flower, who've spoken out and have tried, but have failed. They are heros, and nothing is stopping the current batch. Unfortunately nothing can be done unless Mugabe steps down.