Hi,
I didn’t notice which operating system you are using. In many OS’s the question mark is not a valid character for use in file names (along with / : and *). In the case of the question mark it is because it acts as a single character “wild-card” when searching for a file. So a search for fred?.mp3 could actually access fred1.mp3 fred9.mp3 freda.mp3 or fredz.mp3 (just a few of many possibilities).
The best advice I can give would be to rename filenames containing ? to something more widely compatible.