Hi everyone,need some help here

i have installed market access on my tab,the problem is i can't access the market because it sayi dont have su..so i installed superuser 2.3.6.1

but when i enter to superuser it says that another superuser 2.3.1-signed.zip has in my sdcard..it says that i need to update mu su binary thru recovery mode and flash it but i have try so many times in recovery mode but it keep failing

someone,need help here