The Solution Manager Diagnostics provides powerful tools to run your IT landscape efficiently and to identify and rectify problems quickly. It is therefore imperative that the Managed System Configuration is performed correctly and to check that data is reported to the Solution Manager.
If you experience any issues with missing data in Work Load Analysis please use this methodical approach to narrowing down and solving the issue. It is called Problem Resolution Procedure (PRP):
http://wiki.scn.sap.com/wiki/display/SMSETUP/SMS_CHECK_WELCOME?original_fqdn=wiki.sdn.sap.com
The page consists of a neat explanation of the different data extraction methods followed by the links to the actual PRP's at the bottom of the page
