Maybe renaming the following folders could help (which will result into the standard game without any addons etc.).
Close the client and go to the base directory
"c:\users\<your windows username>\documents\The Elder Scrolls Online\live" (or "C:\...liveeu" if you play on the EU servers).
The following folders should be renamed/deleted/moved:
AddOns
SavedVariables (<- this most probably will have a file like "ZO_Ingame.lua" which maybe the error initiator).
Rename them to AddOns_BACKUP and SavedVariables_BACKUP for example.
And then rename the file AddOnSettings.txt too, for example AddOnSettings.txt_BACKUP
Delete the file ShaderCache.cooked (shouldn#t have to do with it but just to be sure
)
Maybe rename the file UserSettings.txt too, which will have you to setup all settings ingame again.
Otherwise, if I understood you wrong and you've already deleted all the folders in this directory before:
Nevermind and good luck to solve the issue.