Using Qt 4.8.2 with OpenCV 2.4 Library Problem

[omaroo161]

I'm trying to use Qt with OpenCV Library on Windows 7 64 bit on Qt Creator and Visual Studio 2010.
When I edit the *.pro file to add OpenCV x64 libraries and the header files needed in an empty project (Non Qt project), the OpenCV library works fine but when I try to work using Qt and OpenCV, I open a new Qt Empty Project and edit the *.pro file to add the x64 libraries (or even the x86 libraries) and the header files, I get error message "The application was unable to start correctly (0xc000007b). Click Ok to close the application.". I searched for this error and found that I get it when 32 bit application tries to call 64 bit *.dll.
Could anyone help me solve this problem ?
Thank you very much.

[high_flyer]

Yes, match the DLL to your platform (x64/x32).