you need to add the parameters which you want to use in the first line
function repairVehicle(thePlayer)--,commandName,argument1,argument2)
in addition, I have no clue what this line is supposed to mean
local vehicle = getPedOccupiedVehicle(g_Me)
you should change this to
local vehicle = getPedOccupiedVehicle(thePlayer)
g_Me is not even a function, some lazy scripters are used to add a line to their CLIENT SIDE SCRIPT which says g_Me = getLocalPlayer() and makes g_Me return the player that belongs to the client.