If you tried to root using the motochopper exploit, the su binary update is failing because you aren't really rooted. AT&T S4s running 4.2.2 have a locked bootloader which causes everything but the ADB push of superuser to fail. Prove it to yourself by downloading and running the Root Checker
I don't know of anyway around this currently, but I'm sure it's just a matter of time. Interestingly, there is a 1-click method (ar.apk) for rooting the AT&T S4 Active, which also has locked bootloader.