Thank you very much.
I was trying to find a way to protect the files with the data folder in the wwwroot/owncloud, but the easiest way to get rid of the security issue is moving the data folder.viewtopic.php?f=17&t=7118&p=27761&hilit=windows+iis#p27761
1. Stop IIS server.
2. Move your files to the path desired.
3. Find your config.php (c:\inetpub\wwwroot\owncloud\config).
4. Where it says "datadirectory", place the path of your new directory using \\ between folders instead of \.
For example, i moved them to (don't forget the ,):
'datadirectory' => 'C:\\ownCloud\\data',
5. Restart IIS.
You may need to enter in the new data directory and grant some privileges extras (Right click on the folder>Properties>Security) for each file or folder, but at least like these you fix the problem.