rooting Ninetec Platinum 10 failed

[hajo2121]

I tried to root my Ninetec Platinum 10 with superoneclick. the program says rooting succeeded. then i instlled superSU (2,40).
when opening SU it wants an update, i treid everything to update but no chance. status 255 installation failed. checking with root checker says not rooted.
does anyone have an idea
thanks in advance

 

[hajo2121]

is there nowbody out there that can help??
i will attach 2 pictures... the su file is read only.. how can i change it and or is that the problem?