RAID 5 issue with Smart Array 6412

[HP Smart Array 6412]

I had one Server HP-DL380 G4. It was working fine till yesterday. A RAID 5 was configured on this server and had four disks.
I extract the disks (4 disks) and attached to them on another server (HP Proliant G4P)with the Hardware RAID.
When I installed the disk to the Proliant server, it was showing the disks in RAID array. Later I disconnected all the four drives from the server as I no backup devices was available with me that time.
In evening when I tried again to attached the same four disks, it was showing "RAID" failure.
I'm worried if the data still exists on the four drives or it would have been deleted / removed. Just for your information I haven't configured anything (Array or RAID or Logical Disk)during the setup.

Please let me know at the earliest.....

Regards
Alok Sharma