Due to a problem during the Installation of Microsoft Exchange Server resp. SharePoint 2013 it is not possible to run web applications within the IIS in 32bit mode anymore.
You will find detailed information at:

Every server running Microsoft Exchange Server resp. SharePoint 2013 is affected. That means every Small Business Server (SBS), too. 32bit AppPools are needed by the DocuWare Web Components. Unfortunately Microsoft doesn't provide any other solution than fixing the configuration in IIS manually.

Install DocuWare like on any other server. After the installation accessing the Web Client results in a HTTP 503 Error.
In order to fix this, download the batch file attached to this article.
Copy it locally and run the batch file with local administrator privileges (right click - "Run as administrator").
Run the bat file only, if you have installed the DocuWare Web Components in Default Web Site, otherwise please contact DocuWare Support.