The closest thing I could figure out to the reason SDoc is failing on Windows

cp_r_failure.rb

require 'fileutils'
Dir.mkdir 'src' unless Dir.exist?('src')
Dir.mkdir 'dest' unless Dir.exist?('dest')

FileUtils.cp_r 'src/.', 'dest', :preserve => true
puts "run 'explorer dest' and try again"

error output from script

PS C:\Users\Justin\Projects\Ruby\test> .\test.rb
run 'explorer dest' and try again
PS C:\Users\Justin\Projects\Ruby\test> explorer dest
# With the explorer window open
PS C:\Users\Justin\Projects\Ruby\test> .\test.rb
C:/SDK/Ruby/Ruby193/lib/ruby/1.9.1/fileutils.rb:1379:in `utime': Permission denied - dest/. (Errno::EACCES)
        from C:/SDK/Ruby/Ruby193/lib/ruby/1.9.1/fileutils.rb:1379:in `copy_metadata'
        from C:/SDK/Ruby/Ruby193/lib/ruby/1.9.1/fileutils.rb:466:in `block in copy_entry'
        from C:/SDK/Ruby/Ruby193/lib/ruby/1.9.1/fileutils.rb:1433:in `preorder_traverse'
        from C:/SDK/Ruby/Ruby193/lib/ruby/1.9.1/fileutils.rb:462:in `copy_entry'
        from C:/SDK/Ruby/Ruby193/lib/ruby/1.9.1/fileutils.rb:437:in `block in cp_r'
        from C:/SDK/Ruby/Ruby193/lib/ruby/1.9.1/fileutils.rb:1515:in `block in fu_each_src_dest'
        from C:/SDK/Ruby/Ruby193/lib/ruby/1.9.1/fileutils.rb:1529:in `fu_each_src_dest0'
        from C:/SDK/Ruby/Ruby193/lib/ruby/1.9.1/fileutils.rb:1513:in `fu_each_src_dest'
        from C:/SDK/Ruby/Ruby193/lib/ruby/1.9.1/fileutils.rb:436:in `cp_r'
        from C:/Users/Justin/Projects/Ruby/test/test.rb:5:in `<main>'

error output from sdoc

PS C:\Users\Justin\Projects> git clone git://github.com/voloko/sdoc.git
Cloning into 'sdoc'...
remote: Counting objects: 1647, done.
remote: Compressing objects: 100% (788/788), done.
remote: Total 1647 (delta 817), reused 1586 (delta 769)
Receiving objects: 100% (1647/1647), 536.07 KiB | 244 KiB/s, done.
Resolving deltas: 100% (817/817), done.
PS C:\Users\Justin\Projects> cd sdoc
C:\Users\Justin\Projects\sdoc
PS C:\Users\Justin\Projects\sdoc> rake install
sdoc 0.3.15 built to pkg/sdoc-0.3.15.gem
sdoc (0.3.15) installed
PS C:\Users\Justin\Projects\sdoc> sdoc --debug
Parsing sources...
100% [12/12]  README.rdoc

Generating SDoc format into C:/Users/Justin/Projects/sdoc/doc...
Copying C:/SDK/Ruby/Ruby193/lib/ruby/gems/1.9.1/gems/sdoc-0.3.15/lib/rdoc/generator/template/sdoc/resources/./
** to C:/Users/Justin/Projects/sdoc/doc/**
Permission denied - C:/Users/Justin/Projects/sdoc/doc/.
C:/SDK/Ruby/Ruby193/lib/ruby/1.9.1/fileutils.rb:1379:in `utime'
        C:/SDK/Ruby/Ruby193/lib/ruby/1.9.1/fileutils.rb:1379:in `copy_metadata'
        C:/SDK/Ruby/Ruby193/lib/ruby/1.9.1/fileutils.rb:466:in `block in copy_entry'
        C:/SDK/Ruby/Ruby193/lib/ruby/1.9.1/fileutils.rb:1433:in `preorder_traverse'
        C:/SDK/Ruby/Ruby193/lib/ruby/1.9.1/fileutils.rb:462:in `copy_entry'
        C:/SDK/Ruby/Ruby193/lib/ruby/1.9.1/fileutils.rb:437:in `block in cp_r'
        C:/SDK/Ruby/Ruby193/lib/ruby/1.9.1/fileutils.rb:1515:in `block in fu_each_src_dest'
        C:/SDK/Ruby/Ruby193/lib/ruby/1.9.1/fileutils.rb:1529:in `fu_each_src_dest0'
        C:/SDK/Ruby/Ruby193/lib/ruby/1.9.1/fileutils.rb:1513:in `fu_each_src_dest'
        C:/SDK/Ruby/Ruby193/lib/ruby/1.9.1/fileutils.rb:436:in `cp_r'
        C:/SDK/Ruby/Ruby193/lib/ruby/gems/1.9.1/gems/sdoc-0.3.15/lib/sdoc/generator.rb:367:in `copy_resources'

        C:/SDK/Ruby/Ruby193/lib/ruby/gems/1.9.1/gems/sdoc-0.3.15/lib/sdoc/generator.rb:170:in `generate'
        C:/SDK/Ruby/Ruby193/lib/ruby/gems/1.9.1/gems/rdoc-3.12/lib/rdoc/rdoc.rb:493:in `block in generate'
        C:/SDK/Ruby/Ruby193/lib/ruby/gems/1.9.1/gems/rdoc-3.12/lib/rdoc/rdoc.rb:488:in `chdir'
        C:/SDK/Ruby/Ruby193/lib/ruby/gems/1.9.1/gems/rdoc-3.12/lib/rdoc/rdoc.rb:488:in `generate'
        C:/SDK/Ruby/Ruby193/lib/ruby/gems/1.9.1/gems/rdoc-3.12/lib/rdoc/rdoc.rb:471:in `document'
        C:/SDK/Ruby/Ruby193/lib/ruby/gems/1.9.1/gems/sdoc-0.3.15/bin/sdoc:7:in `<top (required)>'
        C:/SDK/Ruby/Ruby193/bin/sdoc:19:in `load'
        C:/SDK/Ruby/Ruby193/bin/sdoc:19:in `<main>'