When in creative and going through pages my players say they are crashing out and I have tested it out but stuck on what it is. So I'm trying to match the log to a mod some where but very hard to understand cause I see no mod or block names in the crash.
Minecraft crash report
http://pastebin.com/wcjnxuke

Unless you are sure it is an issue with BoP, please don't report the issue here. Also, 1.6.4 is no longer supported.