How to create a video for a map?

Hello! I'm having an issue and would appreciate some help. I'm creating a cutscene in the map editor. The editor displays and plays it correctly, everything seems fine. I save the map, go back to the regular map editor, and in the property tree, under the StartScene tab, I select this scene. The path to it remains correct, and the editor recognizes it. However, when I enter the game, nothing happens; not even a black screen appears for a second – it's as if the cutscene doesn't exist. Then, I tried to launch it using the StartDialogScene script. I've made sure the path is correct, and the script seems fine too, but the console still says "DialogScene not exist." Can you please explain how the editor can see and play the cutscene, while the console claims it doesn't exist?
The script looks like this:
StartDialogScene("/DialogScenes/MyM1/S1/DialogScene.xdb#xpointer(/DialogScene)");
The path is correct, and the script seems to be as well, but the console says otherwise...