Wolfguardd

so my friends and i setup a server of mods we liked (its essentially a modified Attack of the B-Team server, modified in the sense that it has everything attack of the b-team does plus some extras) after some tweaking the server loads and people were able to join however when people discover certain areas the server crashes and after restarting the server they try to reconnect and it crashes again, i can delete theyre player data on the server and they can rejoin just fine, but anytime anyone goes to that area the server crashes and in order to stay up and let them play again i need to delete their server side player data im guessing theres a mod conflict but am still new to setting up minecraft servers and modding minecraft, oh and if i have the world restarted (but using same seed) the locations that cause this change. heres the crash report http://pastebin.com/kRbfxDFw