Database Software

On my 2-node RAC database on VMWare machine...i have problem with asm disk...
Platform: linux AS5
RDBMS: 10.2.0.5


sql>select name,group_number,state from v$asm_diskgroup
NAME GROUP_NUMBER STATE
--------------- ------------ -----------
DATA 0 DISMOUNTED
FLASH 2 MOUNTED

Then I found...
SQL> SELECT NAME,PATH,MOUNT_STATUS,HEADER_STATUS,GROUP_NUMBER FROM V$ASM_DISK
NAME PATH MOUNT_S HEADER_STATU GROUP_NUMBER
--------------- ------------------ ------- ------------ ------------
/dev/raw/raw3 CLOSED MEMBER 0
/dev/raw/raw6 CLOSED MEMBER 0
/dev/raw/raw2 CLOSED FOREIGN 0
/dev/raw/raw1 CLOSED FOREIGN 0
FLASH_0001 /dev/raw/raw7 CACHED MEMBER 2
FLASH_0000 /dev/raw/raw4 CACHED MEMBER 2

I tried to mount the data diskgroup...
SQL> ALTER DISKGROUP DATA MOUNT;
ALTER DISKGROUP DATA MOUNT
*
ERROR at line 1:
ORA-15032: not all alterations performed
ORA-15130: diskgroup "DATA" is being dismounted
ORA-15066: offlining disk "DATA_0001" may result in a data loss

Then I tried to drop the disk "DATA_0001" ...
SQL> ALTER DISKGROUP DATA DROP DISKS IN FAILGROUP DATA_0001;
ALTER DISKGROUP DATA DROP DISKS IN FAILGROUP DATA_0001
*
ERROR at line 1:
ORA-15032: not all alterations performed
ORA-15001: diskgroup "DATA" does not exist or is not mounted

ASMCMD> ls
DATA/
FLASH/
ASMCMD> cd DATA/
asmcmd: diskgroup 'DATA' does not exist or is not mounted
.....

On OS level its...all disk are available...
please is there any solution...