Lua error with 4.98

[b-morgan]

I got the following error after updating to 4.98 and then logging in after today's maintenance.

1x Guildbook\Core.lua:2227: attempt to index global 'GuildbookOptionsShowSpecAndMainCharacterGuildChat' (a nil value)
[string "@Guildbook\Core.lua"]:2227: in function Init' [string "@Guildbook\Core.lua"]:4721: in function ?'
[string "@Guildbook\Core.lua"]:5036: in function <Guildbook\Core.lua:5034>

Locals:
self =

{
Database = {
}
SendGuildCalendarEventDeleted = defined @Guildbook\Core.lua:4516
DebugColours = {
}
OptionsInterface = {
}
addonLoaded = false
DEBUG = defined @Guildbook\Debugger.lua:118
UnregisterComm = defined @Questie\Libs\CallbackHandler-1.0\CallbackHandler-1.0.lua:153
ProfessionNames = {
}
dropdownWidgets = {
}
CHAT_MSG_SYSTEM = defined @Guildbook\Core.lua:4816
BankRequests = {
}
GUILD_INVITE_REQUEST = defined @Guildbook\Core.lua:5015
SendGuildCalendarDeletedEvents = defined @Guildbook\Core.lua:4645
ImportGuildTradeskillRecipes = defined @Guildbook\Core.lua:2968
GUILD_ROSTER_UPDATE = defined @Guildbook\Core.lua:4836
GetGuildMemberGUID = defined @Guildbook\Core.lua:3755
OnGuildCalendarEventAttendReceived = defined @Guildbook\Core.lua:4495
ADDON_LOADED = defined @Guildbook\Core.lua:4719
ScanPlayerContainers = defined @Guildbook\Core.lua:3044
CalendarWorldEvents = {
}
BankCharacters = {
}
RequestGuildBankCommits = defined @Guildbook\Core.lua:4289
BAG_UPDATE_DELAYED = defined @Guildbook\Core.lua:4845
SendCommMessage = defined @Questie\Libs\AceComm-3.0\AceComm-3.0.lua:87
GetGuildName = defined @Guildbook\Core.lua:2770
PrintMessage = defined @Guildbook\Core.lua:2780
UnregisterAllComm = defined @Questie\Libs\CallbackHandler-1.0\CallbackHandler-1.0.lua:174
version = 4.980000
LoadTime = 445314.822000
Tradeskills = {
}
GetLocaleProf = defined @Guildbook\Core.lua:2707
BANKFRAME_CLOSED = defined @Guildbook\Core.lua:4863
OnPrivacyReceived = defined @Guildbook\Core.lua:4084
RegisterComm = defined @Questie\Libs\AceComm-3.0\AceComm-3.0.lua:60
ON_COMMS_RECEIVED = defined @Guildbook\Core.lua:4883
RequestTradeskillData = defined @Guildbook\Core.lua:3168
DB_OnDataRequest = defined @Guildbook\Core.lua:3969
OnGuildBankCommitReceived = defined @Guildbook\Core.lua:4323
DebuggerWindow = GuildbookDebugFrame {
}
CHAT_MSG_WHISPER = defined @Guildbook\Core.lua:4790
SetupGuildCalendarFrame = defined @Guildbook\Calendar.lua:32
OnGuildCalendarEventsReceived = defined @Guildbook\Core.lua:4567
BANKFRAME_OPENED = defined @Guildbook\Core.lua:4851
RequestGuildCalendarEvents = defined @Guildbook\Core.lua:4437
ScanPlayerBank = defined @Guildbook\Core.lua:3139
dropdownFlyouts = {
}
CHAT_MSG_GUILD = defined @Guildbook\Core.lua:4760
ModBlizzUI = defined @Guildbook\ModBlizzUI.lua:56
GetClassSpecAtlasName = defined @Guildbook\Core.lua:2720
Data = {
}
UPDATE_MOUSEOVER_UNIT = defined @Guildbook\Core.lua:4725
OnGuildCalendarEventUpdated = defined @Guildbook\Core.lua:4689
PushEventUpdate = defined @Guildbook\Core.lua:4680
DB_SendCharacterData = defined @Guildbook\Core.lua:3987
FONT_COLOUR = "|cff0070DE"
SendPrivacyInfo = defined @Guildbook\Core.lua:4059
OnTradeSkillsRequested = defined @Guildbook\Core.lua:4207
EventFrame = GuildbookEventFrame {
}
OnGuildCalendarEv