Didn't we sort of already know that Bill Murray was to blame for the hold ups? I mean he hated the original script so buddies Dan Aykroyd and Harold Ramis decided to take over duties and rework things. He spouted off about wanting to die in the opening sequence and come back as a ghost...

Follow up:

Today, however, all speculation aside we hear from a fellow GHOSTBUSTER himself, Ernie Hudson. Who thus far has remained quite about the project. Here is what Ernie had to say:

"Dan and Harold are working on the script. If it happens we will see but Bill has been the hold up. His definition of good is a little bit different than everybody elses. So we will see, I would love to see it happen. I know the fans have been asking for it ... so hopefully. Bill's a great guy, he's kind of quirky but I love him. He's a guy who is very much into what he's feeling. I know he really cares about his work, which is probably why there hasn't been another Ghostbusters as of yet."

From what we know so far it appears as if Columbia Pictures is looking to start production May of 2011 although at this point, who really knows for sure. This is one of those cases where we are going to believe it, when we see it!

Source: Movie Mikes