From the wrf files, I'm seeing in DS2WebA0, DS2WebB0, DS2WebC0 that not all the threads are connecting to the DS2DB0, while tile 1 is working fine.
Could you double check that you have followed the directions in the benchmarking guide, "Configure Windows to Not Use a Proxy Server" for each of your clients? In LAN settings, having any of the checkboxes "Automatically detect settings", "Use automatic configuration script" or "Use a proxy server for your LAN", checked can cause this problem.
I also noticed inconsistencies in the domain qualifiers:
tile0 DS2DB: vmark25.cirr.tile0
tile0 DS2Web VMs: cirr.tile0
tile1 DS2DB: maildomain1.vmark25.cirr.tile0
tile1 DS2Web VMs: maildomain1.cirr.tile0.
I find this odd as it's not necessary to have the SLES VM joined to the maildomain (these domains are for the benefit of the Mailserver workload only). Typically the domain qualifier for these vms would be your company's domain only. In any case, you might check the inconsistency between DS2Web tile0 and tile1 domains.
Thanks,
Rebecca