diff --git runtime/syntax/vim.vim runtime/syntax/vim.vim
index c809f70..cbebc7c 100644
--- runtime/syntax/vim.vim
+++ runtime/syntax/vim.vim
@@ -759,9 +759,9 @@ if !filereadable(s:mzschemepath)
 endif
 if (g:vimsyn_embed =~# 'm' && has("mzscheme")) && filereadable(s:mzschemepath)
  unlet! b:current_syntax
- let iskKeep= &isk
+ let s:iskKeep= &isk
  exe "syn include @vimMzSchemeScript ".s:mzschemepath
- let &isk= iskKeep
+ let &isk= s:iskKeep
  VimFoldm syn region vimMzSchemeRegion matchgroup=vimScriptDelim start=+mz\%[scheme]\s*<<\s*\z(.*\)$+ end=+^\z1$+	contains=@vimMzSchemeScript
  VimFoldm syn region vimMzSchemeRegion matchgroup=vimScriptDelim start=+mz\%[scheme]\s*<<\s*$+ end=+\.$+		contains=@vimMzSchemeScript
  syn cluster vimFuncBodyList	add=vimMzSchemeRegion