Hardware check for dell servers fails

hi all ,
i have a problem with the nagios check raid disk in one of my dell server
i get an output from my nagios that says :

[root@sql3 ~]# /usr/local/nagios/libexec/check_perc5i.pl
[size=150]OK [/size]- VirtualDrives=2, Degraded=1, Offline=0, PhysicalDevices=7, Disks=6, CriticalDisks=0, FailedDisks=1, MemoryCorrectableErrors=0, MemoryUncorrectableErrors=0

1 disk is failed but yet nagios returns an OK message.
does anyone know / had this problem in the past ?

the server that he is monitoring is DELL PowerEdge 2950

thanks all.

Try this one
http://folk.uio.no/trondham/software/check_openmanage.html