DraStic

when ever i try to move roms to my sd card either from my pc or from my nvidia shield i start getting decrypt errors and invalid rom errors when ever i try to load a rom how can i fix this?

i keep getting this error "this is not a valid rom" on a previous thread i thought i fixed it but i did not all my games have been tested on my computer and they work also getting another error on some games saying its encrypted and i need arm7 bios which is weird because i dont get any errors on my ...

so i bought drastic and it was working great but now any time i try to open a rom it says "The file you tried to open is not a valid rom"
they where working fine before so i dont know whats wrong im using nvidia shield android 4.4.2 any help would be great thanks!