ML310 storage server 'error'Hp management services failed to retrive logical disks'

[MKumar Nagappa]

box - g4 ml310 storage server
os - hp oem ms windows 2003 storage server sp1
raid controller smart e200 - 4disk x 500gb raid 5 set

without any pattern at any time the users lose theie connection to the shared drive data. then after 30 seconds or a minute
the user get the connection back / or they have to log out & log in. but the data they were working in at that time is either lost or not updated.

at that time eventvwr records event id 4160 'Failed to retrieve logical disks. An unexpected exception was thrown'

ran hp online diagnostics no disk error of any sort found.