disable NERD Tree plugin because it breaks in Vim 7.4

It shows an error message whenever I try to open gVim to a file, such as by double-clicking a file in Windows Explorer.

I hope NERD Tree updates soon and I enable it again. Or, if the problem is a conflict with my config, I hope that someone writes a guide for fixing that.
set new Vim 7.4 `j` formatoption
add initial version of blank-line replacement for } and {