There is a known issue in the WCF Services SDK which may soon cause you at least a really annoying message; "this operation is not supported for a relative uri". While it is not fatal and you can ignore it – as a matter of good coding, I tend to get rid of as many warning messages as possible. To fix it, open your machine.config (both x86 and x64 version), and delete the following section:

C:\Windows\Microsoft.NET\Framework\v4.0.30319\Config\machine.config
C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Config\machine.config

<endpoint address="" binding="netTcpRelayBinding" 
 contract="IMetadataExchange" name="sb" />