Vmware vcenter 5.1 installation with FQDN error

I'm trying to install vCenter 5.1 on a windows 2012 dedicated (with SQL express standalone)
During the installation of the Single Sign On module i've a warning
"the fully qualified domain name cannot be resolved with nslookup. if you continue the installation some features might not work correctly. for detailed requiments see the installation and setup guide"

The only indication that i've found are about the reverse zone dns resolution.. and this works!

• i've verified that the dns works properly with nslookup

C:\Users\admin>nslookup srv6.mydomain.local
Server:  srv2.mydomain.local
Address:  172.25.4.22
Nome:    srv6.mydomain.local
Address:  172.25.1.26


C:\Users\admin>nslookup 172.25.1.26
Server:  srv2.mydomain.local
Address:  172.25.4.22

Nome:    srv6.mydomain.local
Address:  172.25.1.26

(all ip are right: I've the vCenter=srv6 and DC+DNS=srv2 on different vlan)

• i've tryed to force the resolution of the ip changing the [..]\drivers\etc\hosts file

• i've disabled the IPv6 support

• i've used all combination with domain prefixes (explicit, by dhcp, undefined..)
• i've disabled all antivirus/firewall (kaspersky end point 10)

is this a bug of vcenter 5.1.0-1065152 ?
have you got any suggestions for me?