We are in a similar situation. We downloaded the DirectShow demos for webcam videos and also the components in the trial version. The demo executables worked correctly but when compiling the demo source code with the demo components, TImageEnView does not display the webcam image.
If our demos work, but when you compile the demos yourself they do not work, it is possible that the lack of a digital signature blocks the functionality. We sign all of our EXE files with an OV code signing certificate from: