What version of the product are you using?
2.2.59

Do you have an error log of what happened?
 1x RaidTracker-2.2.59\RaidTracker.lua:397 table index is nil
RaidTracker-2.2.59\RaidTracker.lua:259 in function `OnEventCustom'
LibKarma-1.0-? (RaidTracker):138: in function `_OnUpdate'
LibKarma-1.0-? (RaidTracker):38: in function <...ddOns\RaidTracker\libs\LibKarma-1.0\LibKarma-1.0.lua:38

Locals:
self = <table> {
 CanAutoCreateLog = <function> @ RaidTracker\RaidTracker.lua:307
 _update = <table> {}
 UpdateSessionDB = <function> @ RaidTracker\RaidTracker.lua:382
 AddWipeDB = <function> @ RaidTracker\RaidTracker.lua:505
 _options = <table> {}
 OnLoadCustom = <function> @ RaidTracker\RaidTracker.lua:3
 UpdateInstanceDB = <function> @ RaidTracker\RaidTracker.lua:465
 OnPlayerLogin = <function> @ RaidTracker\RaidTracker.lua:24
 EndSessionDB = <function> @ RaidTracker\RaidTracker.lua:571
 SortToggle = <function> @ RaidTracker\RaidTracker.lua:1386
 _store = <table> {}
 _acelib = <table> {}
 DeleteSessionDB = <function> @ RaidTracker\RaidTracker.lua:592
 AddLootItemDB = <function> @ RaidTracker\RaidTracker.lua:700
 L = <table> {}
 AddEventDB = <function> @ RaidTracker\RaidTracker.lua:448
 GetPage = <function> @ RaidTracker\RaidTracker.lua:1432
 Select = <function> @ RaidTracker\RaidTracker.lua:1410
 CreateLootItemDB = <function> @ RaidTracker\RaidTracker.lua:640
 GetAttendeeUnitId = <function> @ RaidTracker\RaidTracker.lua:337
 OnCommandCustom = <function> @ RaidTracker\RaidTracker.lua:43
 UpdateLootTargetDB = <function> @ RaidTracker\RaidTracker.lua:423
 FrameUpdateView = <function> @ RaidTracker\RaidTracker.lua:952
 _db = <table> {}
 GetLink = <function> @ RaidTracker\RaidTracker.lua:751
 CreateSessionDB = <function> @ RaidTracker\RaidTracker.lua:545
 CompareItems = <function> @ RaidTracker\RaidTracker.lua:905
 SnapshotSessionDB = <function> @ RaidTracker\RaidTracker.lua:617
 FrameUpdate = <function> @ RaidTracker\RaidTracker.lua:819
 GoBack = <function> @ RaidTracker\RaidTracker.lua:1449
 GetRaidTitle = <function> @ RaidTracker\RaidTracker.lua:765
 GetTimestamp = <function> @ RaidTracker\RaidTracker.lua:761
 GetDisplayDate = <function> @ RaidTracker\RaidTracker.lua:757
 GetLinkMeta = <function> @ RaidTracker\RaidTracker.lua:745
 _GetAttendees = <function> @ RaidTracker\RaidTracker.lua:367
 OnEventCustom = <function> @ RaidTracker\RaidTracker.lua:137
 GetAttendeeCount = <function> @ RaidTracker\RaidTracker.lua:324
 GetAttendeeInfo = <function> @ RaidTracker\RaidTracker.lua:344
 GetAttendeesType = <function> @ RaidTracker\RaidTracker.lua:315
 GetStatusText = <function> @ RaidTracker\RaidTracker.lua:798
 TruncateSessionDB = <function> @ RaidTracker\RaidTracker.lua:610
 _meta = <table> {}
 _instance = <table> {}
 GetAttendees = <function> @ RaidTracker\RaidTracker.lua:360
 AddGuildDB = <function> @ RaidTracker\RaidTracker.lua:520
 UpdateZoneDB = <function> @ RaidTracker\RaidTracker.lua:482
}
frame = RaidTrackerFrame {
 0 = <userdata>
 LastPage = <table> {}
}
event = "PLAYER_ENTERING_WORLD"
db = <table> {
 Zones = <table> {}
 ItemOptions = <table> {}
 Options = <table> {}
 Bosses = <table> {}
 SortOptions = <table> {}
 Online = <table> {}
 Log = <table> {}
}
o = <table> {
 AutoSolo = 0
 LogWipe = 0
 CurrentRaid = 1
 AutoRaid = 3
 VersionFix = 35
 AutoEvent = 0
 LogRarity = 5
 LogILevel = 0
 EventCooldown = 0
 LogAttendees = 1
 ItemOptionsSelected = 2
 EventLast = 3371.094
 AutoParty = 0
 BossName = "Trash mob"
}
L = <table> {
 1 = <table> {}
 2 = <table> {}
 3 = <table> {}
 4 = <table> {}
  ---