Im not too proficient in helping with crash logs but it looks like you might not have all the mods installed. all you would need to do to fix it is re download the pack and make sure you have the correct mods installed.
Crash of the Titans has gotten a new update, 1.20, and we will be updating the server to this version. This updates requires a world reset, unfortunately. We are sorry to do this such short notice, but this newer version is more stable and will be better for the server in the long run.