SQL> DECLARE
   2    TYPE ParamsArrayType IS TABLE OF VARCHAR2( 4000 );
   3    ParamsArray ParamsArrayType := ParamsArrayType();
   4   BEGIN
   5    EXECUTE IMMEDIATE
   6     '
  7     DECLARE
  8      ParamsArray ParamsArrayType := :1; 
  9     BEGIN
 10      NULL;
 11     END;
 12     
 13    ' USING ParamsArray;
  14     NULL;
  15   END;
  16   /
  ' USING ParamsArray;
          *
ERROR at line  13 :
ORA- 06550 : line  13 , column  11 :
PLS- 00457 : expressions have to be of SQL types
ORA- 06550 : line  5 , column  2 :
PL/SQL: Statement ignored

SQL> CREATE OR REPLACE TYPE ParamsArrayType IS TABLE OF VARCHAR2( 4000 );
   2   /

Type created.

Elapsed:  00 : 00 : 01 . 32 
SQL> 
SQL> 
SQL> DECLARE
   2    ParamsArray ParamsArrayType := ParamsArrayType();
   3   BEGIN
   4    
   5    EXECUTE IMMEDIATE
   6    '
  7   DECLARE
  8    ParamsArray ParamsArrayType := :1; 
  9   BEGIN
 10    NULL;
 11   END;
 12   ' USING ParamsArray;
  13    
  14     NULL;
  15   END;
  16   /

PL/SQL procedure successfully completed.