You need to actually call the function in the keybind. You currently only added the name there, without the () to start it.
That's why it tells you "function arguments expected" as you defined the function to be called, but no arguments/parameters.
Code:
<Down>SmarterAutoLoot:SALToggle</Down>
->
Code:
<Down>SmarterAutoLoot:SALToggle()</Down>
If this does not work try the . notation instead:
Code:
<Down>SmarterAutoLoot.SALToggle(SmarterAutoLoot)</Down>