Constant lua errors on Classic Anniversary server

Message: ...ildbook_ClassicEra/Views/GuildRoster/GuildRoster.lua:165: attempt to compare nil with string
Time: Mon Mar 10 08:10:18 2025
Count: 18
Stack: ...ildbook_ClassicEra/Views/GuildRoster/GuildRoster.lua:165: attempt to compare nil with string
[string "@Interface/AddOns/Guildbook_ClassicEra/Views/GuildRoster/GuildRoster.lua"]:165: in function <...ildbook_ClassicEra/Views/GuildRoster/GuildRoster.lua:160>
[string "=[C]"]: in function `sort'
[string "@Interface/AddOns/Guildbook_ClassicEra/Views/GuildRoster/GuildRoster.lua"]:160: in function `Update'
[string "@Interface/AddOns/Guildbook_ClassicEra/Views/GuildRoster/GuildRoster.lua"]:188: in function <...ildbook_ClassicEra/Views/GuildRoster/GuildRoster.lua:187>
[string "=[C]"]: ?
[string "@Interface/AddOns/Blizzard_SharedXMLBase/CallbackRegistry.lua"]:144: in function <...e/AddOns/Blizzard_SharedXMLBase/CallbackRegistry.lua:143>
[string "=[C]"]: ?
[string "@Interface/AddOns/Blizzard_SharedXMLBase/CallbackRegistry.lua"]:147: in function `TriggerEvent'
[string "@Interface/AddOns/Guildbook_ClassicEra/Events.lua"]:796: in function `?'
[string "@Interface/AddOns/Guildbook_ClassicEra/Events.lua"]:65: in function <Interface/AddOns/Guildbook_ClassicEra/Events.lua:63>

Locals: a = <table> {
 data = <table> {
 }
}
b = <table> {
 data = <table> {
 }
}
(*temporary) = nil
(*temporary) = "Orgrimmar"
(*temporary) = "attempt to compare nil with string"

and

Message: ...ildbook_ClassicEra/Views/GuildRoster/GuildRoster.lua:165: attempt to compare string with nil
Time: Mon Mar 10 08:09:03 2025
Count: 15
Stack: ...ildbook_ClassicEra/Views/GuildRoster/GuildRoster.lua:165: attempt to compare string with nil
[string "@Interface/AddOns/Guildbook_ClassicEra/Views/GuildRoster/GuildRoster.lua"]:165: in function <...ildbook_ClassicEra/Views/GuildRoster/GuildRoster.lua:160>
[string "=[C]"]: in function `sort'
[string "@Interface/AddOns/Guildbook_ClassicEra/Views/GuildRoster/GuildRoster.lua"]:160: in function `Update'
[string "@Interface/AddOns/Guildbook_ClassicEra/Views/GuildRoster/GuildRoster.lua"]:188: in function <...ildbook_ClassicEra/Views/GuildRoster/GuildRoster.lua:187>
[string "=[C]"]: ?
[string "@Interface/AddOns/Blizzard_SharedXMLBase/CallbackRegistry.lua"]:144: in function <...e/AddOns/Blizzard_SharedXMLBase/CallbackRegistry.lua:143>
[string "=[C]"]: ?
[string "@Interface/AddOns/Blizzard_SharedXMLBase/CallbackRegistry.lua"]:147: in function `TriggerEvent'
[string "@Interface/AddOns/Guildbook_ClassicEra/Events.lua"]:796: in function `?'
[string "@Interface/AddOns/Guildbook_ClassicEra/Events.lua"]:65: in function <Interface/AddOns/Guildbook_ClassicEra/Events.lua:63>

Locals: a = <table> {
 data = <table> {
 }
}
b = <table> {
 data = <table> {
 }
}
(*temporary) = "Orgrimmar"
(*temporary) = nil
(*temporary) = "attempt to compare string with nil"