Can you please try to access the application with a different username?
If yes then you should run the following query on the database: DELETE FROM <appname>_USERPARAMS WHERE Username like '<username>@%' and Parameterkey = 'UserMbrSel'
The root cause of the above error is a faulty Data form/Data Grid design which anyone try to run with particular POV. This issue can come up when you have row with Scalc or with NoSuppress option and you have also selected in the data form design the option to Suppress the row with Nodata/Invalid/Zero. This can be conflicting/ambiguous when user selects a POV for which the data form comes up with Nodata/Zero/Invalid rows and hence throws the above error.