My game crashes when I try to use the Worldshaper's Sextant. I point at a block, right click, and the game crashes after freezing up for a second or two. This happens consistently whenever I attempt to use the item. So far, nothing else causes a crash like this.

FML Log: http://pastebin.com/MGryARw4

You don't have CodeChickenCore installed.
Seems like Vazkii imported the wrong Vector class :3

Thank you. Didn't realize I needed CodeChicken.

You've not supposed to need it, it's happened before it's just a mis-import when using the Vector class.