Same issue here with Windows 2008 R2 SP1 on ESXi 5.1. Underlying storage didn't seem to matter any as I tested using the local disks (SAS) and the SAN (Nimble array). Both presented the issue. Tried with VM tools installed and without with same issue.
Works fine with DHCP and breaks with Static IP address.
Tried a number of different MS fixes, none made any difference.
http://support.microsoft.com/kb/938449 - none of the options fixed issue.
STP is off on our HP Procurve switches.
We're also running XenServer 5.6SP2 (migrating off XenServer to VMWare), no issue in our XenServer environment or on our physical machines which points to VMWare. Both XenServer and VMWare are running on the same Procurve switches. All VM traffic is on dedicated ports (not shared with management traffic).
Found that using DHCP Reservations was a workaround, doesn't help for DC's though.
How are others getting around this issue on DC's?