Mihai Sarbulesco, Support Escalation Engineer from Romania, have written a cool blog post on troubleshooting and fixing a Service Manager Data Warehouse registration. The blog post includes a small Tool that migth solve your DW issue.
You can read the blog post here: http://blogs.technet.com/b/mihai/archive/2014/10/13/fixing-service-manager-data-warehouse-registration-information.aspx
Thank you Mihai, for writing this post.