Same happened to me during Utlima HM fight (I was around 10% left ><).

Same to my group on Turn 2

Character: Pia Lior
World: Hyperion
Zone: Porta Ducama (or whatever xD)
Raid: Ultima Hard Mode
Date and Time: 12/30/2013 7:30PM-7:50PM(PST)
Error: 90000 kicked my group from Duty Finder server, Error 10105 prevented logging back in (exactlly the same for me)