Oracle Message ORA-12088 - cannot online redefine table string.string with unsupported datatype

ERRORcannot online redefine table string.string with unsupported datatype
CAUSEAn attempt was made to online redefine a table containing a LONG column, an ADT column, or a FILE column.
ACTIONDo not attempt to online redefine a table containing a LONG column, an ADT column, or a FILE column.