Hello;
I’ve just found your Vita download links broken.
Your links point to RetroArch.7z which does not exist, only RetroArch.vpk and RetroArch_data.7z:
https://buildbot.libretro.com/stable/1.6.9/playstation/vita/RetroArch.vpk https://buildbot.libretro.com/stable/1.6.9/playstation/vita/RetroArch_data.7z
Cheers