When trying to select two normal CT images (loaded via DICOM, ask Alfred for test data) in the PointBasedRegistration PlugIn, there is an error message "Only 2D or 3D images can be processed.".
I could simply fix the bug by commenting out line 140 - 145 in QmitkPointBasedRegistrationView.cpp:
*if( _image->GetDimension() == 4)
QMessageBox::information( NULL, "PointBasedRegistration", "Only 2D or 3D images can be processed.", QMessageBox::Ok );
... but the input data check it also gone with this quickfix. However, in my case (registration of two CT images), the plugin was working fine afterwards.