I've ran WorldLingo to translate that

.. So if none of this is even the slightest related to what you've asked, blame WorldLingo for that XD
The big flash player that my template also has as a special feature (Use the Diff template that comes with the package to enable it) also has the ability to display video files in the form of
FLash
Video files (.FLV) or regular flash files (.SWF). Some other video formates are supported using Windows Media Player (or any other media player that supports streaming) to stream the file from the server; but still, only a few formats are suppoted.
If your videos are not in the form of a Flash video, i suggest that you convert them.. cause i dont know of any other way to make it possible.
As for the second thing.
Sure you can personalize it. Just check out Style.css (inside the "\template\css" folder); you can change a lot of settings there.
To change the background image, change this part of code:
body {
margin: 10px;
scrollbar-face-color: #DEE3E7;
scrollbar-highlight-color: #FFF;
scrollbar-shadow-color: #DEE3E7;
scrollbar-3dlight-color: #C7C3AE;
scrollbar-arrow-color: #069;
scrollbar-track-color: #EFEFEF;
scrollbar-darkshadow-color: #98AAB1;
background: #F3F5F8 url(/template/images/back.gif) repeat-x;
}
You can also change the icons to whatever format you want, just change this part of code inside the template:
<td class="row1" align="center" valign="middle" height="50"><a href="%item-url%" class="messageimagelink"><img src="/template/icons/file.gif" width="64" height="64" border="0"/></td>
Its located in every [file.EXT] section where EXT stands for the extension you want to change. (in the code above, look for <img src="path goes here"/>)
I hope this helps. =D
Ps. rejetto ^^ im from The Netherlands, not Germany