Region Error (FPS Drop To 0)

Hello, I'm Yali and I'm the co-owner of a vanilla smp private server. Our server is fairly new, and it's been running about 5 months. Our server is hosted by beastnode.com and we currently have 33 active members. My bug issue is some sort of chunk error. Next to our spawn, we have a trail of corrupt chunks of sorts. When this area is entered, FPS and chunk updates instantly drop to 0. I have tried using the repair feature in MCedit, I have tried regenerating the chunks, and deleting them completely. I later discovered that these errors weren't quite by "chunk". Certain areas of a specific chunk were fine, and other areas corrupt. Everyone on the server experiences the same issue, so it's not specific to a player or computer. I have also tried moving our world to single player, and I experienced the same problem. We began experiencing this issue in 1.7.5, and the server currently runs on snapshot 14w21b. I'd appreciate any help I can get. Thanks.

EDIT: This does not look like a chunk error (hole in the world). The world looks completely fine. This issue occurs when the area is entered. The image I have included shows a black and yellow taped off area. As you can see, the area looks fine. When you walk or fly into that area, FPS and chunk updates drop to 0.