i only get HW errors with my 280x and cgminer-3.7.2-sj-0.02 with this settings. what can i do?

--scrypt-jane --sj-nfmin 4 --sj-nfmax 30 --sj-time 1388949883 --gpu-threads 1 -I 12 -g 2 -w 256 --thread-concurrency 11200 --gpu-dyninterval 7 --lookup-gap 2 --shaders 2048
with --sj-time 1430892923 i get just rejects (share is above target).
