[Q] Help me please. topic

Hi I have some problem for my GT-I9500 i want to update os to I9500XXUGNI1 so I try to update by myself but my device is show error

Skipping MD5 check : no MD5 file not found
Error flashing zip '/external_sd/THL - I9500XXUGNI1 - 20141001141614.zip'
Updating partition details...
...done