I decided to create my own modpack to start using instead of tekkit, in hopes of reducing lag. Originally I was playing tekkit with the tinker's construct mod added. A picture of my custom mods folder is attached to this. As I neared where my base and quarry was, the game crashed. I thought this could have been due to all of the water and empty space lagging out the game when it was trying to load the chunks, although using mcedit to fill it in with dirt did nothing. Please help as I really don't want to start over with this new modpack.
Crash report: http://paste.ubuntu.com/11784490/
UPDATE: I think it may have something to do with block id's not being the same as what they were set to in tekkit.