Case-Sensitive FileType

With vim 7.4 (at least patch 507) autocmd is seems to got case sensitive regarding filetype.
I receive the following error upon opening vim for some time:
>Error detected while processing /home/mp/.vim/bundle/nerdtree-git-plugin/nerdtree_plugin/git_status.vim:
>line  257:
>E216: No such event: nerdtree call s:AddHighlighting()