Datapatch failed because of no PDB

Hi,

I have installed R12.2.0 on windows 2012 R2. I have installed vision instance using express option, on single node.Now i am upgrading to R12.2.7 . i have applied latest Opatch and database patch 21821214 successfully. Datapatch is failing  with error "catconInit: database is not open on the default instance".After days of struggle i found it is failing because of no PDB found.Datpatch -verbose -debug produced following information.

user_pdbs:

Connecting to database...OK

not container database!

$VAR1 = 'Data::Dumper';

$VAR2 = {

          'undef' => {

                       'startup_mode' => 'READ WRITE',

                       'pdb_name' => undef,

                       'bootstrap_log' => undef

                     }

        };

$VAR1 = 'Data::Dumper';

$VAR2 = [

          undef

        ];

catconInit failed, exiting