This isn't a rep problem. As far as I know, only bloodelfs can start those BE starter quests. I had the same problem with my mixed racial group. Since I couldn't do the BE starter quests, I did the undead starter quests instead. When you reach level 5, the BE quests at falconwing square become available and those can be started by any horde race (even though you're still neutral with the bloodelfs).