Red face json file missing

Hi guys, hope some 1 out there can help when I try to update my roms I get the json file is missing
i think at some point my SD card got deleted I have tried changing repositories in ROM updater and new rooms show up but none of them will update
I downloaded 1 rom stuck in on the SD card and tried to load custom ROM from there but it came up with error..so its a while since i done all this and a bit lost on what do do ..how do i update to the latest rom thanks in advance