The reason we ask for information about the DBMS you're using is because Single Sign-On functionality is implemented by the database interface client. Are you using SQL Server, Oracle, SQL Anywhere, Postgres, ODBC, etc.? What version? What version/release/build of PB are you using? Which PB database interface (SQLCA.DBMS='???') does your app use? What version of Windows does your app run on?
This information is necessary in order for anyone to be able to help you.