Bukkit

What steps will reproduce the problem?
1. fban a user that is not on the forum
2. fban a user that is on the forum
3. funban the user that was not on the forum

then every funban afterwards crashes server

What is the expected output? What do you see instead?

/funban crashes server instead of unbanning users

What version of the product are you using?

latest ( v3.4.0 )
Craftbukkit 1597
GroupManager

Do you have an error log of what happened?

No, server litterally crashes to the point i have to HTOP and kill java process...

Please provide any additional information below.

This is hindering our forum, as even if we /unban a user, they are still banned SOMEWHERE (we even take them out of the forum group "Banned")

Using vBulletin 4.1.5 as well.
Using MySQL (setup correctly as it was working previously)

Also, per world, we have different groups... is there some way there could be implemented the ability to create a new field to accommodate the groups in different worlds? cause we have a survival world (reduced to 2 groups, where main world has 12) and we cannot get the staff to go into the staff group automatically...

general:
    mode: normal
    enable-whitelist: 'false'
    enable-nickname-syncing: 'false'
    enable-synced-banning: 'true'
    enable-promotion-track: 'true'
    enable-rank-changing: 'true'
    enable-post-count-rewarding: 'false'
modes:
    normal:
        user-table: user
        minecraft-login-name-field: username
        rank-id-field: usergroupid
        multitable:
            enable-multiple-tables: 'false'
            second-table: second_table
            user-id-field-in-user-table: user_id_field_user_table
            user-id-field-in-second-table: user_id_field_second_table
    secure:
        forum: xenforo
        type1:
            user-table: mybb_users
            username-field: username
            password-field: password
            rank-id-field: usergroup
        type2:
            user-table: user_table
            username-field: username_field
            password-field: password_field
            rank-id-field: rank_group_field
            location-of-passgen-php: http://yoursite.com/passgen.php
            password-set-in-config-inc-php: 12345pass
        type3:
            user-table: xf_user
            rank-id-field: user_group_id
            username-field: username
            password-field: data
            second-table: xf_user_authenticate
            user-id-field-in-user-table: user_id
            user-id-field-in-second-table: user_id
        type4:
            user-table: user_table
            username-field: username_field
            password-field: password-field
            rank-id-field: rank_group_field
            location-of-passgen-php: http://yoursite.com/passgen.php
            password-set-in-config-inc-php: 12345pass
mysql-connection:
    mysql-host: localhost
    mysql-user: xxxxxxxxx
    mysql-password: xxxxxxxxxxxx
    mysql-database-name: vbulletin
    mysql-port: '3306'
#Map your rank IDs to groups here. world-specific overwrites default. You NEED atleast 1
#entry under worlds, even if the world doesn't exist.
group-mapping:
    default:
        '1': Default
        '2': Builder
        '9': VIPIron
        '10': VIPGold
        '13': VIPDiamond
        '7': Moderator
        '6': Admin
        '11': Owner
        '12': Developer
    worlds:
        world:
            '1': Default
            '2': Builder
            '9': VIPIron
            '10': VIPGold
            '13': VIPDiamond
            '7': Moderator
            '6': Admin
            '11': Owner
            '12': Developer
extras:
    whitelist:
        kick-message: This is the message a user will see if their group isn't whitelisted.
        use-as-blacklist: 'true'
        groups:
            '1': 'true'
            '2': 'true'
            '7': 'true'
            '6': 'true'
            '9': 'true'
            '10': 'true'
            '11': 'true'
            '12': 'true'
    nickname-syncing:
        nickname-field-in-usertable: salt
    synced-banning:
        banned-user-forum-rank-id: '8'
        unbanned-user-forum-rank-id: '2'
        ban-message: You have been banned from the server.
    promotion-track:
        track: 1|2|9|10|13|7|6
    rank-changing:
        identifiers:
            '1': Default
            '2': Builder
            '9': VIPIron
            '10': VIPGold
            '13': VIPDiamond
            '7': Moderator
            '6': Admin
            '11': Owner
            '12': Developer
    post-count-rewarding:
        currency-reward-per-post: '40'
        post-count-field-in-user-table: 'like_count'