Windows Server 2008 DNS, Active Directory stops working on HP Proliant DL 380 G5 and G4 servers

[Nosferatu]

Hi,

I have 8 domain controllers HP Proliant DL 380 G5 and G4 servers running MS Windows Server 2008 64Bit Standard/Enterprise Edition.
Each DC is running DNS server and the domain zone are Active Directory integrated.
No previous verson of windows domain controllers are present.
Everything was working fine until recently.
For the past few days, i have been getting the following errors and warnings on all of my DC's on a frequent basis (daily on some, longer on others)

Events: 1925, 1311, 1566,1865
Source: ActiveDirectory_DomainService

Events: 4000, 4015, 4004
Source: DNS-Server-Service

Events: 13508, 13526, 13562
Source: NtFrs

At that point the AD stops working. During this problem, network shares are accesible (also sysvol folder), dns name resolution working correctly but no ad replica are possible, no directory access are possible.
The problems go away temporarily when i restart the servers. But the next day or the day after that, it reappear. There's no specific timing, it's just random.

Let me clarify that nothing was changed. Everything was working fine for more than 4 months. Now all of a sudden, i am starting to have these issues.

I have gone through a lot of articles including the ones below, did all the tests mentioned in those articles. Still couldn't find the source of the problem:

http://technet.microsoft.com/en-us/library/cc778061.aspx
http://technet.microsoft.com/en-us/library/cc736750.aspx
http://technet.microsoft.com/en-us/library/bb727056.aspx

Any help would greatly be appreciated. Thanks in advance.

Regards

[Nosferatu]

Still waiting for a reply..