Volume name and file system type disappeared

[HDS-HSSET]

We've a Windows Storage Server running on Proliant DL380 with MSA50 providing storage.
We created a logical disk and formatted it as NTFS volume.
All of a sudden,we're not able to access the volume anymore.
Disk Management showed the volume name and file system gone. But when we checked the Properties of the volume, it still has volume name. Attach the screenshot.

The event log showed
Event Type: Error
Event Source: HP Storage Server Management Service
Event Category: None
Event ID: 4160
Date: 9/11/2007
Time: 8:06:01 PM
User: N/A
Computer: CLYIS001
Description:
Failed to retrieve logical disks. An unexpected exception was thrown.

What could be the cause?
What can be done to recover the volume?
How to ensure it doesn't happen again?

Thanks.

[Michael Lorenz]

We have the same Problem on our HP Storage Server DL 380 except the fact that there is no Event-ID 4160 and the Volume is still accessible. No need to attach a screenshot, because it looks exactly the same as the screenshot the first author attached.

First we suggested a Filesystem Error. So we createc a new Volume, copied all the Files into the new Volume and after that the error was also present on the new Volume.

Any Ideas?

Thx