bhop gamemode and some questions

hi so i want to make a bhop server i have the gamemode and all but i have some questions

you have any suggests ? like the gravity and that stuff cus i dont know

and for some reason i have this error :

[ERROR] RunString:1: unexpected symbol near '404'
  1. unknown - RunString:0

now i dont know if its because the gamemode or someting else and i dont know how to fix it