I'm not really good with crash reports but everything seems to point at a problem with Mekanism. Just to go out on a limb here try checking that your version of Mekanism is supported by your version of Forge. If this dose not help I'm sure someone with more knowledge can sort it out for you, just takes them some time to get to posts. Just try to be patient.
Rollback Post to RevisionRollBack
When angry, count to four; when very angry, swear. Samuel Langhorne Clemens
When angry, count to four; when very angry, swear. Samuel Langhorne Clemens
If you do update you may as well check that all of your mods are updated just to prevent any issues.
When angry, count to four; when very angry, swear. Samuel Langhorne Clemens