Dear Sir or Madam,
 
how are you?
 
First: Thanks for the validation service. It is of great use!
 
I would like to report a problem. I have searched the e-Mail-Archive and the Bug database. I have found but one note about HTML5+microdata being unintentionally validated as successful.
However, my problem is different:
 
Three sites of mine contain microcode for a song list. Google Webmaster Tools Structured Data Test has no problems detecting and interpreting the microdata. However, validator.w3c.org and validator.nu both complain about each itemprop:
 
"The itemprop attribute was specified, but the element is not a property of any item."
 
Below is the source code snippet that contains the corresponding part for one site. The other two sites are:
www.tales-beyond-reason.com
www.tales-beyond-reason.de
 
Thank you very much for your support!
Kind regards,
 
Michael Schreiber
 
---
URL: www.jp.tales-beyond-reason.com
 
SOURCE:
(...)
        <ol itemscope itemtype="http://schema.org/MusicGroup" itemprop="name" content="Tales Beyond Reason" >
          <li itemprop="tracks" itemscope itemtype="http://schema.org/MusicRecording">
            <meta itemprop="name" content="「霧の森」" />
            <meta itemprop="alternateName" content="「MistyWoods」" />
            <meta itemprop="image" content="www.jp.tales-beyond-reason.com/images/TBR_01_Misty%20Woods.jpg" />
            <meta itemprop="duration" content="PT1M45S" />
            <meta itemprop="inAlbum" content="Tales Beyond Reason EP" />
            <meta itemprop="offers" content="tales-beyond-reason.bandcamp.com/track/misty-woods" />
            <meta itemprop="url" content="http://www.tales-beyond-reason.com/media/TBR_01_Misty%20Woods.mp4" />
            <?php echo('<a itemprop="video" href="' . $_SERVER['PHP_SELF'] . '?track=1#player">'); ?>
              霧の森、<span lang="en">「Ｍｉｓｔｙ Ｗｏｏｄｓ」</span>
            </a>
          </li>
          <li itemprop="tracks" itemscope itemtype="http://schema.org/MusicRecording">
            <meta itemprop="name" content="「ダゴン」" />
            <meta itemprop="alternateName" content="「Dagon」" />
            <meta itemprop="image" content="www.jp.tales-beyond-reason.com/images/TBR_02_Dagon.jpg" />
            <meta itemprop="duration" content="PT2M13S" />
            <meta itemprop="inAlbum" content="Tales Beyond Reason EP" />
            <meta itemprop="offers" content="tales-beyond-reason.bandcamp.com/track/dagon" />
            <meta itemprop="url" content="http://www.tales-beyond-reason.com/media/TBR_02_Dagon.mp4" />
            <?php echo('<a itemprop="video" href="' . $_SERVER['PHP_SELF'] . '?track=2#player">'); ?>
              ダゴン、<span lang="en">「Ｄａｇｏｎ」</span>
            </a>
          </li>
          <li itemprop="tracks" itemscope itemtype="http://schema.org/MusicRecording">
            <meta itemprop="name" content="「サールナートに来ドウーム」" />
            <meta itemprop="alternateName" content="「The Doom That Came to Sarnath」" />
            <meta itemprop="image" content="www.jp.tales-beyond-reason.com/images/TBR_03_The%20Doom%20That%20Came%20to%20Sarnath.jpg" />
            <meta itemprop="duration" content="PT2M9S" />
            <meta itemprop="inAlbum" content="Tales Beyond Reason EP" />
            <meta itemprop="offers" content="tales-beyond-reason.bandcamp.com/track/the-doom-that-came-to-sarnath" />
            <meta itemprop="url" content="http://www.tales-beyond-reason.com/media/TBR_03_The%20Doom%20That%20Came%20to%20Sarnath.mp4" />
            <?php echo('<a itemprop="video" href="' . $_SERVER['PHP_SELF'] . '?track=3#player">'); ?>
              サールナートに来ドウーム、<span lang="en">「Ｔｈｅ Ｄｏｏｍ Ｔｈａｔ Ｃａｍｅ ｔｏ Ｓａｒｎａｔｈ」</span>
            </a>
          </li>
          <li itemprop="tracks" itemscope itemtype="http://schema.org/MusicRecording">
            <meta itemprop="name" content="「ただ一度覗くだけ」" />
            <meta itemprop="alternateName" content="「Just a Glance」" />
            <meta itemprop="image" content="www.jp.tales-beyond-reason.com/images/TBR_04_Just%20a%20Glance.jpg" />
            <meta itemprop="duration" content="PT2M28S" />
            <meta itemprop="inAlbum" content="Tales Beyond Reason EP" />
            <meta itemprop="offers" content="tales-beyond-reason.bandcamp.com/track/just-a-glance" />
            <meta itemprop="url" content="http://www.tales-beyond-reason.com/media/TBR_04_Just%20a%20Glance.mp4" />
            <?php echo('<a itemprop="video" href="' . $_SERVER['PHP_SELF'] . '?track=4#player">'); ?>
              ただ一度覗くだけ、<span lang="en">「Ｊｕｓｔ ａ Ｇｌａｎｃｅ」</span>
            </a>
          </li>
          <li itemprop="tracks" itemscope itemtype="http://schema.org/MusicRecording">
            <meta itemprop="name" content="「夢」" />
            <meta itemprop="alternateName" content="「A Dream」" />
            <meta itemprop="image" content="www.jp.tales-beyond-reason.com/images/TBR_05_A%20Dream.jpg" />
            <meta itemprop="duration" content="PT2M27S" />
            <meta itemprop="inAlbum" content="Tales Beyond Reason EP" />
            <meta itemprop="offers" content="tales-beyond-reason.bandcamp.com/track/a-dream" />
            <meta itemprop="url" content="http://www.tales-beyond-reason.com/media/TBR_05_A%20Dream.mp4" />
            <?php echo('<a itemprop="video" href="' . $_SERVER['PHP_SELF'] . '?track=5#player">'); ?>
              夢、<span lang="en">「Ａ Ｄｒｅａｍ」</span>
            </a>
          </li>
        </ol>
(...)