Im quit unsure on what this crash is caused by. This crash has just been going on and preventing anyone from playing on my server.
Any help?
That build is several out of date. Can you try using the latest SpongeForge (accessible from spongeforge)?
I updated and the same crash occurs
Can you post a log of the updated build? Line numbers of crashes often change between builds so it is vital to provide a log for every time you run with a version change.
This is a Pixelmon issue that will be fixed in the later builds.