Hello, could you please tell us what program and version you are using.
Could you also tell us exactly what the error message is, or post a screenshot.
Magix Video Deluxe does have trouble loading some particular types of MOV files. It also has trouble with some "weird", non-standard MP3s. This can be worked-around though.
Your serial number remove by @emmrecs beginning with P2- would suggest you are running a very old version of the software from 2014 or earlier, is this correct?
What is the full name of the software and version number as found under Help, About?
Are you getting a popup message which says Quicktime is required, if so then download and install Quicktime from here. Only install the checked options in the installer dialog.
If there is no popup message and the MOV or MP4 file just do not load then we need more information.
The specification of your computer system including Windows version and program version, see this topic for what is required and please quote processor and graphics card make/model in full, and also what monitor/screen resolution(s) you are working with if this is a laptop.
I would suggest you put this information in your profile signature so we do not have to keep asking for it.
Download and install MediaInfo and analyse one of the clips and post the results, see this tutorial on how to setup MediaInfo and analyse a video clip for all the data required.