查了下资料，对ORA-03120错误的解释是：
ORA-03120 two-task conversion routine: integer overflowCause: An integer value in an internal Oracle structure overflowed when being sent or received over a heterogeneous connection. This can happen when an invalid buffer length or too great a row count is specified. It usually indicates a bug in the user application.Action: Check parameters to Oracle calls. If the problem recurs, reduce all
integer parameters, column values not included, to less than 32767.
ORA-03120 two-task conversion routine: integer overflowCause: An integer value in an internal Oracle structure overflowed when being sent or received over a heterogeneous connection. This can happen when an invalid buffer length or too great a row count is specified. It usually indicates a bug in the user application.Action: Check parameters to Oracle calls. If the problem recurs, reduce all
integer parameters, column values not included, to less than 32767.
exp username/password buffer=102400 file=c:\aaa.dmp