After upgrade to BA 6.0 (less than 6.0.3) different operations in BA control panel return error:
Invalid result on line 103
Issue has been confirmed as product bug with id #APS-24732 (PBA-62174: UI interface errors after upgrade to PBA 6.0)
Issue is fixed in BA 6.0.3. Consider to upgrade BA to the latest 6.0 version (or at least 6.0.3 version).
As a temporary workaround BA services may be restarted.