start application: Why this error and how to solve it?

[Colx007]

In English: Error to start the application because didn’t find QtCore4.ddl. The reinstallation cans solution the problem.

I tried to start a *.exe, And I didn’t programmed it, is only an example from qt assistant, bat the problem is presented always that a want to start a *.exe without use the command prompt.

Thanks for all.