To fix lockscreen go to settings-display-lockscreen wallpaper>choose old gallery (green/blue icon) select any picture and set....
MAKE SURE U HAVE A LIVE WALLPAPER SET ALL HOMESCREEN WALLPAPER FIRST!!
Reboot to recovery... 3 button method or through cwm app
Wipe cache partition
Fix permission and reboot
This has been tested numerous times by me and always worked
Sent from my GT-I9100 using XDA Premium App
DEVICES:galaxy s2, xperia play, htc sensation, htc desire, hyc desire hd,galaxy s3,galaxy nexus, lg nexus 4,asus tf101,padfone 2,nexus 7 tab. Galaxy tab