Qt + VTK + MAC version based compilation and execution

I have successfully Built and compiled VTK with Qt on Mac osx 10.6.7. Then according to the requirements I changed configuration in CMAKE so that the target version is 10.5. I compiled VTK with Qt again and it was successful, with cones tutorials examples running. But whenever i compile my own application which is built using QVTK Widget i got this error

"Check with the developer to make sure Application works with this version of MacOS X. You may need to reinstall the application ..."

Following is my CMAKE Configuration

BUILD_EXAMPLES                checked
BUILD_SHARED_LIBS             checked
CMAKE_OSX_ARCHITECTURES       x86_64
CMAKE_OSX_DEPLOYMENT_TARGET   10.5
CMAKE_OSX_SYSROOT             /Developer/SDKs/MacOSX10.5.sdk
VTK_USE_COCOA                 ch开发者_C百科ecked
VTK_USE_CARBON                unchecked
VTK_USE_QT                    checked
VTK_USE_QVT_QTOPENGL          checked

I have also ran following command on the terminal

export MACOSX_DEPLOYMENT_TARGET=10.5

Every thing in my application compiles with both QtCreator and XCode but does not execute by giving the error as mentioned above.

In the above if i change everything from 10.5 to 10.6 everything start working. But according to requirement i need to have it compatible with 10.5.

Can someone please let me know is there anything else i need to do? Am i missing something here?

Regards, Rashid