Just tested the newest build 4.0.1 together with ElvUI and got this LUA error upon loading into the game.

1x Interface/AddOns/BetterWardrobe/Plugins/ElvUI.lua:214: attempt to index field 'ScrollFrame' (a nil value)
[string "@Interface/AddOns/BetterWardrobe/Plugins/ElvUI.lua"]:214: in function <Interface/AddOns/BetterWardrobe/Plugins/ElvUI.lua:117>

Locals:
WardrobeCollectionFrame = BetterWardrobeCollectionFrame {
GetAppearanceItemHyperlink = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1644
SetsTab = BetterWardrobeCollectionFrameTab2 {
}
searchBox = BetterWardrobeCollectionFrameSearchBox {
}
GetActiveTab = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1316
progressBar = StatusBar {
}
selectedTransmogTab = 1
ContentFrames =

{
}
VisualToggle = BetterWardrobeVisualToggle {
}
OnKeyDown = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1519
SetContainer = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1170
GoToSet = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1596
OnShow = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1460
ClickTab = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1200
ItemsTab = BetterWardrobeCollectionFrameTab1 {
}
SavedSetsTab = BetterWardrobeCollectionFrameTab4 {
}
SetSearch = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1693
HideAppearanceTooltip = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1615
GetSearchType = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1708
SetTab = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1207
GoToItem = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1587
UpdateTabButtons = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1601
UpdateProgressBar = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1655
selectedCollectionTab = 1
OpenTransmogLink = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1540
RestartSearchTracking = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1679
Tabs = {
}
SetsTransmogFrame = Frame {
}
SwitchSearchCategory = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1661
SetsCollectionFrame = Frame {
}
ReloadTab = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1157
ItemsCollectionFrame = Frame {
}
FilterButton = Button {
}
BW_SetsHideSlotButton = Button {
}
TransmogOptionsButton = BW_TransmogOptionsButton {
}
ExtraSetsTab = BetterWardrobeCollectionFrameTab3 {
}
GetAppearanceNameTextAndColor = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1635
FilterDropDown = BetterWardrobeFilterDropDown {
}
OnLoad = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1324
OnHide = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1495
SearchBox = BetterWardrobeCollectionFrameSearchBox {
}
CheckTab = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1163
OnEvent = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1338
0 =
numTabs = 4
RefreshCameras = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1629
SetAppearanceTooltip = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1606
ClearSearch = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1702
GetAppearanceSourceTextAndColor = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1640
selectedTab = 1
UpdateUsableAppearances = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:1622
}
SetsCollectionFrame = Frame {
BottomLeftCorner = Texture {
}
ClearAppearanceTooltip = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:5884
LinkSetInChat = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:5943
Center = Texture {
}
GetDefaultSetIDForBaseSet = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:5766
OnBackdropLoaded = defined @Interface/SharedXML/Backdrop.lua:152
0 =
LeftInset = Frame {
}
GetBackdropCo

GEtting the sam eor similar error:

1x ...nterface/AddOns/BetterWardrobe/Plugins/CanIMogIt.lua:67: attempt to index field 'BetterWardrobeCollectionFrameScrollFrameScrollBar' (a nil value)
[string "@Interface/AddOns/BetterWardrobe/Plugins/CanIMogIt.lua"]:67: in function UpdateCanIMogIt' [string "@Interface/AddOns/BetterWardrobe/Modules/Core.lua"]:1368: in function LoadModules'
[string "@Interface/AddOns/BetterWardrobe/Modules/Core.lua"]:1287: in function <Interface/AddOns/BetterWardrobe/Modules/Core.lua:1287>

Locals:
self =

{
TransmogVendorSizeUpdated = true
ViewDelay = 3
useAltSet = false
modules = {
}
Sort = {
}
SecureHook = defined @Interface/AddOns/Ace3/AceHook-3.0/AceHook-3.0.lua:335
tooltip = BW_ProfileTooltip {
}
GetBlizzID = defined @Interface/AddOns/BetterWardrobe/Data/DataBase.lua:408
MogIt = {
}
IsEnabled = defined @Interface/AddOns/Accountant/Libs/AceAddon-3.0/AceAddon-3.0.lua:447
GetActiveCategory = defined @Interface/AddOns/BetterWardrobe/Modules/CollectionList.lua:217
RefreshCharConfig = defined @Interface/AddOns/BetterWardrobe/Modules/Core.lua:1157
RegisterMessage = defined @Interface/AddOns/Accountant/Libs/CallbackHandler-1.0/CallbackHandler-1.0.lua:85
UnregisterMessage = defined @Interface/AddOns/Accountant/Libs/CallbackHandler-1.0/CallbackHandler-1.0.lua:148
validSetCache = {
}
GetBaseList = defined @Interface/AddOns/BetterWardrobe/Data/DataBase.lua:392
db = {
}
SetEnabledState = defined @Interface/AddOns/Accountant/Libs/AceAddon-3.0/AceAddon-3.0.lua:420
Hook = defined @Interface/AddOns/Ace3/AceHook-3.0/AceHook-3.0.lua:273
GetSourceFromItem = defined @Interface/AddOns/BetterWardrobe/Modules/Tooltips.lua:212
InitExtendedSetsSwap = defined @Interface/AddOns/BetterWardrobe/Plugins/ExtendedTransmog.lua:6
OnEnable = defined @Interface/AddOns/BetterWardrobe/Modules/Core.lua:1263
RefreshOutfitData = defined @Interface/AddOns/BetterWardrobe/Modules/Core.lua:871
GetArtifactSourceInfo = defined @Interface/AddOns/BetterWardrobe/Modules/ArtifactAppearances.lua:288
IsWeaponCat = defined @Interface/AddOns/BetterWardrobe/Modules/CollectionList.lua:222
ItemAppearance = {
}
OnInitialize = defined @Interface/AddOns/BetterWardrobe/Modules/Core.lua:1179
itemSourceID = {
}
ColorFilterButton = Button {
}
ColorFilterFrame = Button {
}
Globals = {
}
SortSet = defined @Interface/AddOns/BetterWardrobe/Modules/SortingFunctions.lua:672
Deserialize = defined @Interface/AddOns/Ace3/AceSerializer-3.0/AceSerializer-3.0.lua:246
GetName = defined @Interface/AddOns/Accountant/Libs/AceAddon-3.0/AceAddon-3.0.lua:275
C_TransmogCollection = {
}
Camera = {
}
name = "BetterWardrobe"
UI = {
}
Disable = defined @Interface/AddOns/Accountant/Libs/AceAddon-3.0/AceAddon-3.0.lua:310
GetSetType = defined @Interface/AddOns/BetterWardrobe/Data/DataBase.lua:626
Unhook = defined @Interface/AddOns/Ace3/AceHook-3.0/AceHook-3.0.lua:417
Print = defined @Interface/AddOns/Accountant/Libs/AceConsole-3.0/AceConsole-3.0.lua:50
IsFavoriteItem = defined @Interface/AddOns/BetterWardrobe/Modules/Wardrobe.lua:3496
usableSourceCache = {
}
ExtendTransmogView = defined @Interface/AddOns/BetterWardrobe/Modules/TransmogVendor.lua:423
BuildClassArtifactAppearanceList = defined @Interface/AddOns/BetterWardrobe/Modules/ArtifactAppearances.lua:177
Serialize = defined @Interface/AddOns/Ace3/AceSerializer-3.0/AceSerializer-3.0.lua:122
Init = {
}
CreateChatLinkTransmogVendor = defined @Interface/AddOns/BetterWardrobe/Modules/ImportExport.lua:299
EventHandler = defined @Interface/AddOns/BetterWardrobe/Modules/Core.lua:1374
SelecteSavedList = false
CollectionList = {
}
GetSetCounts = defined @Interface/AddOns/BetterWardrobe/Modules/BlizzardAPI.lua:609
RemoveItemSubstitute = defined @Interface/AddOns/BetterWardrobe/Data/DataBase.lua:899
UnregisterEvent = defined @Interface/AddOns/Accountant/Libs/CallbackHandler-1.0/CallbackHandler-1.0.lua:148
SetDefaultModuleLibraries = defined @Interface/AddOns/Accountant/Libs/AceAddon-3.0/AceAddon-3.0.lua:363
SetsDataProvider = {
}
GetTransmogLocation = defined @Interface/AddOns/Be