The movie is about a group of students and professor go to this haunted house for some reason, They find children's bones in the fireplace and there are ghost children that are constantly popping up everywhere trying to get the attention of and warn the main girl character. I think one of the ghosts is a really mean old guy that looks like scrooge off a christmas carol.

Sounds like The Haunting, came out in 1999...

Could also be "The House on Haunted Hill". "Rose Red"