Error: java.lang.String.equals(java.lang.Object)

Hi All,

             while running the dashboard which is integrated with Enterprise portal, we are getting the below error. These dashboards consumes data from the BEX query  directly using the SAP Netweaver connection Type.

Error Desc:       

                         While trying to invoke the method java.lang.String.equals(java.lang.Object) of a null object loaded from local variable 'lowString'..

Please find the more details in the attached sheet. can any one help me out to resolve this issue.