Backup Error after Hardware/ESXi Version Upgrade

Hi

I have some problems with the Backup of Windows Server VM's since i upgraded my Hardware. Before the Upgrade i used the VMware ESXi Version 5.5 U2 without any problem. Everything works fine, but after changing my Hardware to HP Microserver Gen8 with HP VMware Version 5.5 U3 installed i get some errors every 3-4 days.

I get some different errors, but the most errors are VSS errors. The first VM is a Domain Controller and the second VM is a SQL Server. The following errors comes after 3-4 days and persists until i reboot the server.

Domain Controller Error:
--------------------
Fehlercode: 253
Module: 83
Zeileninfo: c7610e0a857bedf4
Felder:
Nachricht: VMware-Fehler: 'Remote-Methodenaufruf ist fehlgeschlagen.'.

--------------------

Fehlercode: 32
Module: 0
Zeileninfo: c7610e0a857bedf4
Felder:
Nachricht: Erwarteter Task 'CreateSnapshot' fehlgeschlagen. Ursache: An error occurred while saving the snapshot: Failed to quiesce the virtual machine..
--------------------

and later this one:
--------------------

Fehlercode: 3003
Module: 538
Zeileninfo: 38b2393b56c5aa77
Felder:  StringAlertId : ntds vss writer disabled
Nachricht: Alarm 'Konvertierter Agent'

SQL Server Error:

--------------------
Fehlercode: 253
Module: 83
Zeileninfo: c7610e0a857bedf4
Felder:
Nachricht: VMware-Fehler: 'Remote-Methodenaufruf ist fehlgeschlagen.'.

--------------------

Fehlercode: 32
Module: 0
Zeileninfo: c7610e0a857bedf4
Felder:
Nachricht: Erwarteter Task 'CreateSnapshot' fehlgeschlagen. Ursache: An error occurred while saving the snapshot: Failed to quiesce the virtual machine..

--------------------
Fehlercode: 3003
Module: 538
Zeileninfo: 38b2393b56c5aa77
Felder:  StringAlertId : sql vss writer disabled
Nachricht: Alarm 'Konvertierter Agent'

I tried the following things:

1. VMware Tools reinstall (many times)
2. VMware ESXi Update to Version 5.5 U3a (HP Version)
3. Create Snapshot via vCenter without any problem.

I have check the status of the vss writers and noticed that some writers hat the state "Timeout".

Can you help me to solve this problem?

kind regards

Rico