Perhaps you just need to be firm with her? Tell her there are no ghosts in her room, dreams aren't real, etc. When my 5 year old daughter wants me to lie down with her, I tell her I will check on her in a little while. I leave the door open a crack with the hall light on as well as her night light. Half an hour later, if she has been quiet but is still awake, I lie down with her for a few minutes. She likes me to scratch her back and sing songs. I limit it to three and don't really sing, more like whisper the words. Then we lie quietly for a few minutes - I don't let her carry on a conversation - it's time to sleep! If she wants me to stay longer, I tell her again that I will check on her in a little bit. I also tell her what I have to do like wash dishes, check e-mails, whatever. Usually, she will be asleep when I check on her 30 minutes later.
One other note is that my daughter thought dreams could come true. You know how all the princesses have their "dreams" come true by marrying a prince and living happily ever after? She thought that meant dreams the princesses had while sleeping! Something to think about....