Disable Flightcharge EXP

[ItzSheldor]

Description of issue: I want to disable buying Flights with Exp. The Config said, then i need to set the ExpRechargeCost to 0. If i do this, the whole command stops working and i get this message: http://cloud.screenpresso.com/WZu1g/2020-05-17_20h05_44.png

if i set it to sth. like 1.0 everything works.

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CONFIG SECTION (DELETE IF NOT RELEVANT):

FlightCharge:
  # When set to true, each time player gets flight charge or relogs, his fly mode will be toggled on
  # If set to false, then players will have to manually turn on flight with /cmi flyc
  EnabledByDefault: true
  # When set to true, in event of player changing his game mode from survival/adventure to creative/spectator his flight charge  mode will get disabled
  # Same applies when changing game mode from creative/spectator to survival/adventure
  AutoSwitch: false
  # How much it costs for one recharge point in exp points. Value can be in decimals, like 0.2 but it cant be equal or lower than 0
  # Set to 0 to disable this type of recharge
  ExpRechargeCost: 0
  # How much it costs for one recharge point. Value can be in decimals, like 0.2 but it cant be equal or lower than 0
  # Set to 0 to disable this type of recharge
  MoneyRechargeCost: 10.0
  # Defines maximum amount of charge player can have
  # One charge is one traveled block while flying
  # if player doesn't move, then one charge for each second while hovering
  MaxChargeLevel: 1000
  # Defines multiplier when player doesn't move but is hovering. For each second player hovers.
  # Set to 0 to disable
  DeductOnIdling: 2.0
  # If this is set above 0, then player will loose defined amount of charges each second they are flying instead of traveled blocks
  # Set to 0 to disable, which will deduct charges for traveled blocks
  DeductOnlyForTime: 0.0
  # Defines multiplier when player falls down of charge to be taken
  # This only effects when player falls from above 3 blocks of hight
  # In example if player falls from 10 blocks height, then 7 * 2 = 14 charges will be taken
  # This is to prevent avoiding no penalty from jumping from cliffs
  # Set to 0 if you want to disable it
  DeductOnFallMulti: 2
  # Defines if you want to damage player when he falls down from higher than 3 blocks height
  # This will not kill player even if he would drop from 200 block height, but will leave him with 1 hp
  # This will only effect players who jumped down and not those who disabled fly mode in mid air
  DamageOnFall: true
  # DamageOnFall should be enabled for this to work
  # This will define if you want to damage player when he deactivates fly mode in mid air
  DamageOnToggle: false
  # DamageOnFall should be enabled for this to work
  # This will define if you want to kill player if fall damage if higher than his health amount
  KillOnFall: false

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Cmi Version (using/cmi version): CMI Plugin Version: 8.6.25.1 BungeeCord

Server Type (Spigot/Paperspigot/etc): Server Version: Spigot 1.15.2-R0.1-SNAPSHOT Vault Version: 1.7.2-b107

Server Version (using /ver): This server is running CraftBukkit version git-Spigot-800b93f-8160e29 (MC: 1.15.2) (Implementing API version 1.15.2-R0.1-SNAPSHOT)

[Zrips]

Getting a fix