I was struggling with the same issue after I moved my VCDB to another instance of MS SQL. The answer that worked for me was here:
http://www.blog.shonkyholdings.com/2011/12/changing-vcenter-database-within-dsn.html
There was another place where the connection string needed to be updated other than the DSN - the vcdb.properties file. After the first refresh of the vSphere Web Client almost immediately after making a change to this file, I had the Storage Reports view back working.