[My skript command won't work, even though there are no errors.]

I was watching a skript gui tutorial and made this skript: 

command /gui:
 permission: op
 permission message: "&4You can't do this!"
 trigger:
  open virtual chest inventory with size 3 named "&4GUI" to player
  format gui slot 11 of player with grass block named "&2Survival" with lore "&6Change gamemode to:" and "&6Survival"

It looks exactly like how it does in the video but when i reload it it says it was successful but if I do /gui it says unknown command.

[Does anyone have one of those getting items for being afk in an area skript? (or a plugin)]

I've been looking for a plugin or skript that will give players item for being in like an afk pit/room/area like they have in some servers. If anyone could send a skript or plugin link for something like that it would be nice!

[Error in a script I got from a friend. pls help]

I found out what I needed to change: in the options at the beggining it said False and not false like on line 42 so i changed it to false and there were no errors, thanks anyway though!

[Error in a script I got from a friend. pls help]

it does this error now:

[Error in a script I got from a friend. pls help]

[Error in a script I got from a friend. pls help]

options:
    Prefix: &8&l[&c&l!&8&l]
    CT-Time: 10
    MobsCombat-Tag: False

command /combattag:
    aliases: /combatlog,/ct,/cl
    trigger:
        if {combatlog::*} contains player:
            set {_CT.span} to difference between {%player%.combatlog.time} and now
            set {_CT.cd} to "{@CT-Time} seconds" parsed as timespan
            send "{@Prefix} &fYou are Combat Tag for &e%difference between {_CT.span} and {_CT.cd}%"
        else:
            send "{@Prefix} &fYou are not in Combat Tag"
on unload:
    delete {combatlog::*}
    delete {combatlag.blocked-cmds::*}
    delete {kill.combat::*}

on load:
    add "tpa" to {combatlag.blocked-cmds::*}
    add "home" to {combatlag.blocked-cmds::*}
    add "spawn" to {combatlag.blocked-cmds::*}
    add "fly" to {combatlag.blocked-cmds::*}

on damage:
    if attacker is player:
        if attacker is not victim:
            if {combatlog::*} doesn't contain "%attacker%":
                if attacker doesn't have permission "CT.Bypass.Player":
                    add "%attacker%" to {combatlog::*}
                    send "{@Prefix} &fYou are &cCombat Tag &fwith &e%victim%" to attacker
                    console command "/fly %attacker% disable"
            if {combatlog::*} doesn't contain "%victim%":
                if victim doesn't have permission "CT.Bypass.Player":   
                    add "%victim%" to {combatlog::*}
                    send "{@Prefix} &fYou are &cCombat Tag &fwith &e%attacker%" to victim
                    console command "/fly %victim% disable"
            set {%attacker%.combatlog.time} to now
            set {%victim%.combatlog.time} to now
    else:
        if {@MobsCombat-Tag} is true:
            if attacker doesn't have permission "CT.Bypass.Mobs":
                if {combatlog::*} doesn't contain "%attacker%":
                    add "%attacker%" to {combatlog::*}
                    send "{@Prefix} &fYou are &cCombat Tag &fwith &e%victim%" to attacker
                    console command "/fly %attacker% disable"
on command:
    if {combatlog::*} contains player:
        if {combatlag.blocked-cmds::*} contains command:
            cancel event
            send "{@Prefix} &fYou can't use that command while in &cCombat Tag" to player

on join:
    if {kill.combat::*} contains player:
        wait 1 second
        console command "/kill %player%"
        remove player from {kill.combat::*}

on quit:
    if {combatlog::*} contains player:
        loop player's inventory:
            drop loop-value
        clear player's inventory
        add player to {kill.combat::*}
        remove player from {combatlog::*}

on death of player:
    if {combatlog::*} contains player:
        remove player from {combatlog::*}
        
every 1 second:
    loop {combatlog::*}:
        set {_combatlog.gettime} to difference between {%loop-value%.combatlog.time} and now
        if {_combatlog.gettime} > {@CT-Time} seconds:
            remove loop-value from {combatlog::*}
            send "{@Prefix} &fYou are no longer in &cCombat Tag" to loop-value parsed as player