Problem with implementing a DynPro Application inside the portal

Hello,

I've created a Web DynPro Application and deployed it to the Portal.

After that, I've created a DynPro based iView which points to this DynPro Application.

When I test this Application by itself it is working OK but when I activate it through the iView I receive this error:

500 Internal Server Error

The Web Dynpro Application 'AddressBookApp' has expired. Please restart the application either with the refresh button or click the following link AddressBookApp.

What could be the problem here?