Occassionally, when opening a file with vim I get this message:

Error detected while processing BufReadPost Auto commands for "*":
Mark has invalid line number
Press RETURN or enter command to continue

If I press enter, vim opens the file and everything appears to function
normally.  Curious what this actually means and if there's potential to
corrupt the file.

# rpm -qa | grep vim
vim-minimal-5.6-11
vim-enhanced-5.6-11
vim-common-5.6-11

here's my .vimrc:
--------cut here------
set ruler
set showmatch
set showmode
set title
set visualbell
set nohlsearch
syntax on

" SWJ 092199 syntax hilighting didn't work--found this at
" found this gem at http://www.vim.org/vimrc (see Sven's vimrc link)
"
" Set the colors for vim on "xterm"
if &term=="xterm"
  set t_Co=8
  set t_AB=%p1%{8}%<%t%p1%{40}%+%e%p1%{92}%+%;%dm
  set t_AF=%p1%{8}%<%t%p1%{30}%+%e%p1%{82}%+%;%dm
endif
--------cut here------