Every time i put trees near my big nether portal on my flat map world the server crashed D: http://pastebin.com/dQer8c27
Looked at the log. He's using multiverse. He's having issues with the nether portal. Seems logical that the multiverse-netherportal addon might somehow help him out. That's "wat".
I had that issue in the past... fixed it for me. It's almost exactly what happened when I tried to make a nether portal on any map OTHER than the default world... until I used the plugin they made for it. He uses multiverse... he's got an issue with a nether portal... still seems logical that he should at least try it out. Do you have another suggestion for him, or are you just here to complain about me... again... ?