https://forums.atlauncher.com/attachment.php?aid=207

and also this:

http://pastebin.com/diysAFn3

and this:

http://pastebin.com/hTt89qZr

All seem to be similar issues with generating something in BOP, any ideas at all?
Thanks for your time :)

Can't reproduce plus it's a month old. Try updating BOP, deleting WorldCore from mods/1.6.4 and updating Forge to 953. Also, try using the regular launcher rather than the ATLauncher.