VIM在输入时为换行符添加了一个字符

我环顾四周,但没有找到答案.我有一台运行与我的CentOS 5.8服务器相同的. vimrc的CentOS 6.2服务器,但是当我在我的6.2服务器上输入VIM时,它会添加上一行的第一个字符,如果它是某个字符(％或#是我见过的那些).这就是VIM中发生的事情(点击输入后的秒线,但没有输入任何其他内容)：

# <enter>
#

% <enter>
%

这是我的.vimrc：

set autoindent
set smartindent
set tabstop=4
set shiftwidth=4
set showmatch
set number

imap jj <Esc> " Professor VIM says '87% of users prefer jj over esc',jj abrams disagrees

" Indenting *******************************************************************
set ai " Automatically set the indent of a new line (local to buffer)
set si " smartindent (local to buffer)

" Cursor highlights ***********************************************************
"set cursorline
"set cursorcolumn

" Set an orange cursor in insert mode,and a red cursor otherwise.
" Works at least for xterm and rxvt terminals.
" Does not work for gnome terminal,konsole,xfce4-terminal.
"if &term =~ "xterm|rxvt"
"   :silent !echo -ne "33]12;red07"
"   let &t_SI = "33]12;orange07"
"   let &t_EI = "33]12;red07"
"   autocmd VimLeave * :!echo -ne "33]12;red07"
"endif

" Searching *******************************************************************
set hlsearch  " highlight search
set incsearch  " Incremental search,search as you type
set ignorecase " Ignore case when searching
set smartcase " Ignore case when searching lowercase

" Colors **********************************************************************
"set t_Co=256 " 256 colors
set background=dark
syntax on " syntax highlighting
"colorscheme darkzen

对它和我5.8服务器上的那个(我没有这个问题)的差异并没有任何区别.知道为什么会这样吗？