Error: ORA-01031 insufficient privileges upon executing Debugger or using Debugger's Step Over or Trace Into icons. Error may occur in certain schema(s) only.
Grant System Privilege "Alter Any Type" to user which enables user to alter object types in any schema.
If issue is occurring with objects owned by the user, verify that user has sufficient privileges to compile and create objects in his own schema. Note: The Debug Any Procedure grant is not necessary when debugging objects owned by the user, if the Compiling Dependency is turned off, user has sufficient grants to compile/create objects and the Debug Connect Session is granted.