CREATE TABLE xmlTable (Xml XMLType) 

declare 
  poXML CLOB;
BEGIN   
  -- Store the Purchase Order XML in the CLOB variable
  poXML := '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
            <PurchaseOrder>
              <PONum>1001</PONum>
              <Company>Oracle Corp</Company>
            </PurchaseOrder>';
  -- Insert the Purchase Order XML into an XMLType column
  INSERT INTO xmlTable (xml) VALUES (XMLTYPE(poXML));

--Handle the exceptions
EXCEPTION
  WHEN OTHERS THEN 
    raise_application_error(-20101, 'Exception occurred :'||SQLERRM);
end ;

  INSERT INTO xmlTable (Xml) VALUES (XMLTYPE(poXML));
                        *
ERROR at line 11:
ORA-06550: line 11, column 25:
PL/SQL: ORA-19102: XQuery string literal expected
ORA-06550: line 11, column 3:
PL/SQL: SQL Statement ignored

SQL> CREATE TABLE xmlTable (Xml XMLType) ;

Table created.

SQL> declare 
  2    poXML CLOB;
  3  BEGIN   
  4    -- Store the Purchase Order XML in the CLOB variable
  5    poXML := '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
  6              <PurchaseOrder>
  7                <PONum>1001</PONum>
  8                <Company>Oracle Corp</Company>
  9              </PurchaseOrder>';
 10    -- Insert the Purchase Order XML into an XMLType column
 11    INSERT INTO xmlTable (xml) VALUES (XMLTYPE(poXML));
 12  
 13  --Handle the exceptions
 14  EXCEPTION
 15    WHEN OTHERS THEN 
 16      raise_application_error(-20101, 'Exception occurred :'||SQLERRM);
 17  end ;
 18  /
  INSERT INTO xmlTable (xml) VALUES (XMLTYPE(poXML));
                        *
ERROR at line 11:
ORA-06550: line 11, column 25:
PL/SQL: ORA-19102: XQuery string literal expected
ORA-06550: line 11, column 3:
PL/SQL: SQL Statement ignored

SQL> rename xmltable to x;

Table renamed.

SQL> declare 
  2    poXML CLOB;
  3  BEGIN   
  4    -- Store the Purchase Order XML in the CLOB variable
  5    poXML := '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
  6              <PurchaseOrder>
  7                <PONum>1001</PONum>
  8                <Company>Oracle Corp</Company>
  9              </PurchaseOrder>';
 10    -- Insert the Purchase Order XML into an XMLType column
 11    INSERT INTO x  (xml) VALUES (XMLTYPE(poXML));
 12  
 13  end;
 14  /

PL/SQL procedure successfully completed.

SQL> alter session set PLSQL_Warnings = 'enable:all';

Session altered.

SQL> create or replace procedure p
  2  is
  3  begin
  4    raise_application_error(-20000,'Error');
  5  exception when others then null;
  6  end;
  7  /

SP2-0804: Procedure created with compilation warnings

SQL> sho err
Errors for PROCEDURE P:
LINE/COL
---------------------------------------------------------------------------------
ERROR
-----------------------------------------------------------------------------------------

5/16
PLW-06009: procedure "P" OTHERS handler does not end in RAISE or RAISE_APPLICATION_ERROR

SQL> @v

Version Oracle : 11.1.0.6.0