Problems with IE9 and IE10 Second Scrollbar

I checked your website with the w3c validator and it seems like there’re missing paragraph tags in the html code. Maybe these tags cause the styling error. Especially check the content of following html code

<div class='avia_textblock'><blockquote>

<p style="text-align: left;">Die Drei Guten Gründe (3GG) sind eine reine Acoustic-Coverband und bieten für Partys, Hochzeiten, Apéros, Pubs und Firmen Events die perfekte Unterhaltung.</p>

<p style="text-align: left;"></blockquote>

<div class="lyte-wrapper" style="width:420px;max-width: 100%;margin:5px;">

<div class="lyMe" id="WYL_77VknwX_oZ8" itemprop="video" itemscope itemtype="http://schema.org/VideoObject"><meta itemprop="duration" content="T348S" /><meta itemprop="thumbnailUrl" content="http://i.ytimg.com/vi/77VknwX_oZ8/0.jpg" /><meta itemprop="embedURL" content="http://www.youtube.com/embed/77VknwX_oZ8" /><meta itemprop="uploadDate" content="2011-03-03T16:58:51.000Z" /></p>

<div id="lyte_77VknwX_oZ8" data-src="http://i.ytimg.com/vi/77VknwX_oZ8/0.jpg" class="pL">

<div class="tC">

<div class="tT" itemprop="name">3GG Live 2011</div>

</div>