syntaxerror from my markdown helper

gistfile1.txt

SyntaxError: d:/work/Dropbox/Work Sync/bsd/site/mm/source/about.html.erb:2: syntax error, unexpected ')'
; @_out_buf.concat(( md do ).to_s)
                            ^
d:/work/Dropbox/Work Sync/bsd/site/mm/source/about.html.erb:66: syntax error, unexpected keyword_ensure, e
xpecting ')'
d:/work/Dropbox/Work Sync/bsd/site/mm/source/about.html.erb:68: syntax error, unexpected keyword_end, expe
cting ')'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/tilt-1.3.7/lib/tilt/template.rb:227:in `class_eval'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/tilt-1.3.7/lib/tilt/template.rb:227:in `compile_template_metho
d'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/tilt-1.3.7/lib/tilt/template.rb:208:in `compiled_method'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/tilt-1.3.7/lib/tilt/template.rb:143:in `evaluate'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/tilt-1.3.7/lib/tilt/template.rb:77:in `render'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/middleman-core-3.1.5/lib/middleman-core/core_extensions/render
ing.rb:273:in `render_individual_file'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/middleman-core-3.1.5/lib/middleman-core/core_extensions/render
ing.rb:150:in `render_template'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/middleman-core-3.1.5/lib/middleman-core/sitemap/resource.rb:15
0:in `block in render'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/activesupport-3.2.14/lib/active_support/notifications.rb:125:i
n `instrument'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/middleman-core-3.1.5/lib/middleman-core/util.rb:60:in `instrum
ent'
        c:in `instrument'
        c:in `instrument'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/middleman-core-3.1.5/lib/middleman-core/sitemap/resource.rb:12
1:in `render'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/middleman-core-3.1.5/lib/middleman-core/core_extensions/reques
t.rb:252:in `process_request'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/middleman-core-3.1.5/lib/middleman-core/core_extensions/reques
t.rb:202:in `block in call!'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/middleman-core-3.1.5/lib/middleman-core/core_extensions/reques
t.rb:201:in `catch'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/middleman-core-3.1.5/lib/middleman-core/core_extensions/reques
t.rb:201:in `call!'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/middleman-core-3.1.5/lib/middleman-core/core_extensions/reques
t.rb:187:in `call'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/rack-1.5.2/lib/rack/builder.rb:138:in `call'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/rack-1.5.2/lib/rack/urlmap.rb:65:in `block in call'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/rack-1.5.2/lib/rack/urlmap.rb:50:in `call'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/rack-livereload-0.3.15/lib/rack/livereload.rb:23:in `_call'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/rack-livereload-0.3.15/lib/rack/livereload.rb:14:in `call'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/rack-1.5.2/lib/rack/showexceptions.rb:24:in `call'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/rack-1.5.2/lib/rack/lint.rb:49:in `_call'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/rack-1.5.2/lib/rack/lint.rb:37:in `call'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/rack-1.5.2/lib/rack/builder.rb:138:in `call'
        c:/Ruby200/lib/ruby/gems/2.0.0/gems/rack-1.5.2/lib/rack/handler/webrick.rb:60:in `service'
        c:/Ruby200/lib/ruby/2.0.0/webrick/httpserver.rb:138:in `service'
        c:/Ruby200/lib/ruby/2.0.0/webrick/httpserver.rb:94:in `run'
        c:/Ruby200/lib/ruby/2.0.0/webrick/server.rb:295:in `block in start_thread'