to expand on that a little further,if you use a root file browser to navigate to data/media,then you will be able to see all your old files. when this happened to me,i was tempted to just delete data/media/0,and rename data/media to that,but im not sure if there would be wierd side affects to that or not.
what i did was simply restore my stock 4.1 rom,and then when you look with the PC youre veiwing data/media again,so youll just need to copy the files you want to transfer to the PC. restore your 4.2 or 4.3 rom,and then connect to the pc,and drag your pics,ringtones,music,etc. back to where you want them. now theyre in data/media/0 and youre good to go unless you want to go back to 4.1
you can alternately just copy/paste your files from data/media to data/media/0 with root explorer or equivalent root file manager,but it was a little confusing to me keeping track of where i was when doing that. i fonund copying the files to the PC then back to be a bit easier.
hope i didnt just confuse you further.