New chunks not loading client-side

[Cireminer]

Launcher/pack Version: 0.5.4.9, using server 2.1.1 (world 1.1), client 2.1 (world 1.1)

Operating System: Vista

Version of Java: 1.7

Description of Problem: When connecting to a server world that has chunks yet to be loaded, the client will whitescreen. I can load the chunks on single player, then move the world onto a server. Connecting there will be fine until I reach a chunk that hasn't been loaded yet.

I'm not exactly sure when this started occurring, since I've been using pre-generated custom maps for maybe a couple weeks, meaning we didn't generate any new chunks. Just the other day we tried to go beyond the bounds of pre-generated world and we all froze. Had to delete our player files to get back to the spawn area. Now I'm realizing I can't go to new chunks at all, on any world, even newly generated ones.

Error Messages: Worst 'error' I get is the one related to placing a stronghold in an invalid biome, but that seems to be harmless according to other posts, and doesn't always occur when a player tries to generate a chunk.

Link to pastebin of log: http://pastebin.com/AxBpjAMb

Edit: Added the pastebin link. I've downloaded and set up an entirely new server folder, and the crashing no longer occurs. I must've tampered with something in my other server's configs, but I'm not sure what. It'll probably be easier to just use this new folder and re-config the settings than to figure it out, though.