I've had this problem for a while and it really ruins it for me when I become a vampire lord the other vampires don't say anything other than "Do you need something" can anyone help with this?

Should have added been having this problem since dawnguard cameout for PS3

You mean all the vampire characters in Castle Volikhar !!!

It should be a glitch.

Wait for 10 days out of the castle, and then try again.

Or you could delete and re-download Dawnguard.

I've tried re downloading dawnguard before as for the wait 10 days I'll give it a try