On win32 installs with +ruby, ftplugin/ruby.vim makes a call to VIM::command to set the s:ruby_paths variable. In some circumstances, this code can run when under a different ruby module, and if that ruby module has a VIM module defined, there is a namespace clash. The fix is to change the call to be ::VIM::command, which works fine under all cases. The conflict occurs with Command-T in particular when opening a .rb file from that tool.
Most of the file was already indented using spaces, but a few places were using tabs. The modeline was setting "noet" as well. For consistency's sake, the modeline now sets "et" and the file has been retabbed and reindented, excluding the opening header.