Error stopping me from using anything

whenever I press f4 on my server, I get this error. I can not figure out what it means.

[ERROR] gamemodes/darkrp/gamemode/modules/base/sh_gamemode_functions.lua:5: attempt to index field 'Sandbox' (a nil value)
  1. unknown - gamemodes/darkrp/gamemode/modules/base/sh_gamemode_functions.lua:5

Your version isn’t up to date, try updating it first.

just reinstalled from the site

[editline]21st January 2017[/editline]

now I get no error, but the mnu wont pop up f4 and f1