ORA-01567: dropping log 2 would leave less than 2

Hi all

Any idea of this? i can't put the redo log status from unused to another status

GROUP# THREAD# MEMBER                                                                 ARCHIVED   STATUS     Size (MB)

------ ------- ---------------------------------------------------------------------- ---------- ---------- ---------

     2       1 E:\DBGCREP\ORADATA\GCREP\REDO02.LOG                                    YES        INACTIVE          50

     3       1 E:\DBGCREP\ORADATA\GCREP\REDO03.LOG                                    NO         CURRENT           50

     4       2 E:\DBGCREP\ORADATA\GCREP\REDO04A.LOG                                   YES        UNUSED           300

     4       2 F:\DBGCREP\ORADATA\GCREP\REDO04B.LOG                                   YES        UNUSED           300

     5       2 E:\DBGCREP\ORADATA\GCREP\REDO05A.LOG                                   YES        UNUSED           300

     5       2 F:\DBGCREP\ORADATA\GCREP\REDO05B.LOG                                   YES        UNUSED           300

     6       2 E:\DBGCREP\ORADATA\GCREP\REDO06A.LOG                                   YES        UNUSED           300

     6       2 F:\DBGCREP\ORADATA\GCREP\REDO06B.LOG                                   YES        UNUSED           300