Failed to drop column - value too large
You can do it by increasing column size, then drop . 
(Because drop column statement try to validate the data, then drop )
like ..

SQL&gt; ALTER TABLE OWNER.CONFIG
     MODIFY(DTE VARCHAR2(500 BYTE));

SQL&gt; ALTER TABLE OWNER.CONFIG DROP COLUMN DTE ;


example:- 

SQL&gt; select * from v$version ;

BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
PL/SQL Release 11.2.0.4.0 - Production
CORE    11.2.0.4.0      Production
TNS for Linux: Version 11.2.0.4.0 - Production
NLSRTL Version 11.2.0.4.0 - Production


SQL&gt; ALTER TABLE ORCL.FORM DROP COLUMN CURRENT_STEP;
ALTER TABLE ORCL.FORM DROP COLUMN CURRENT_STEP
*

ERROR at line 1:
ORA-12899: value too large for column "ORCL"."FORM"."CURRENT_STEP" (actual:
6, maximum: 2)


SQL&gt; ALTER TABLE ORCL.FORM
  2  MODIFY(CURRENT_STEP VARCHAR2(500 BYTE));


Table altered.


SQL&gt; ALTER TABLE ORCL.FORM DROP COLUMN CURRENT_STEP;


Table altered.