You have 2 choices
You can delete the region file r.-1.0.mcr
Or
You can download NTBExplorer (
http://www.minecraftforum.net/topic/840677-nbtexplorer-nbt-editor-for-windows-and-mac/) , open that region file, find the chunk -19, 16 (have to expand each chunk section until it says xPos -19, yPos 16) and delete all the data in that chunk.
(Edit: In NTBExplorer, when you open that region file it should be 'Chunk [13, 16]' in the list, expand that and delete everything inside it (check it says xPos -19 yPos 16) then save it and readd/reupload it to the servers region folder, I have no idea why the coordinate info differs inside NTBExplorer)
Second option takes more time but you only lose 1 chunk instead of 1024 (region)
Its basically a corrupt pipe in that chunk.
If you run into the issue again in another chunk, use the coordinates listed in the crash report on this to find which chunk it is:
http://dinnerbone.com/minecraft/tools/coordinates/
