The format of 'file:///Users/virginieregnault/Documents/IMG_3901%284%29.mov' cannot be detected. Have a look at the log for details.
If these files were recorded natively on your 4S iPhone, they would be recorded as H.264 video with AAC audio—Apple's default IOS mobile device format. This VLC message could indicate the files you are trying to open could be orphaned "reference" files (a workflow storage issue). For example, here are the messages I get for such files:
QT 7 player
QT X Player
VLC Player
Such files are usually very easy to identify because they contain no playable data and are essentially just a file container pointing to another "standalone" file that contains the actual data. E.g., try opening the Finder Info Window for one your problem files. If it looks something like this:
(i.e., only occupies a few hundred bytes of data in a 4K file container), then this is likely to be your problem. Such files could only be "fixed" if you still have the missing "standalone" file stored/archived somewhere on your system. There could be other, different problems here, but this was the first I found in my "sample problem files" folder that returned the exact error message you indicated above for VLC. This would be a "missing data" issue. To "fix" this particular problem you need the missing original "standalone" file containing the actual encoded data. Without it, you can do nothing. This problem usually occurs when a user either saves the original file as a "reference" file or uses a "reference" file workflow to quickly pass data from one app to another "by reference" to save file space and then keeps the wrong file or moves the "standalone" and/or "reference" files to different locations which effectively "orphans" the data.