after SDK30 Android restricts accessing the file system...
you are not allowed to move files to a random directory of your choice anymore, in your case the VELAVIA directory...
move them to the ASD - Application Specific Directory or the shared storage /Download
see also the overview by @Anke
Taifun
Trying to push the limits! Snippets, Tutorials and Extensions from Pura Vida Apps by 
Taifun.