Go to-Regedit-Open ComputerHKEY_Local_Machine\Software\Microsoft\ExchangeServer\V15\Cafe Role —- and Check out for Watermark Key\if it is exist Delete it and Re-run the Setup.

Disclaimer : Do Not Remove Watermarks As its not Recommended  - Try only on Lab System’s

http://social.technet.microsoft.com/wiki/cfs-filesystemfile.ashx/__key/communityserver-wikis-components-files/00-00-00-00-05/3240.watermark.jpg

http://social.technet.microsoft.com/wiki/contents/articles/12917.exchange-2013-watermark-key-path-in-registry.aspx