I am using Vista x64 Ultimate with ObjectDock 1.9beta build 537u and everything mostly works. I am running my sytem tray inside a dock, and sometimes uTorrent will completely freeze my system while using the system tray.
Normally, when I start uTorrent, I have it selected to go to the system tray and automatically minimize - this works without issue. If I then open uTorrent and re-minimize back to the system tray, it can then crash Vista and ObjectDock - the computer will completely freeze except I can still access Task Manager by pressing ctrl-alt-del. This doesn't happen everytime I minimize uTorrent but has occurred at least 3 times over the last 3 days. The only work around I have now is to not let uTorrent go to the system tray when minimized, but since I often have uTorrent running in the background, I would prefer it in the system tray.
I have Itunes also set up to go to the system tray when minimized - it hasn't crashed ObjectDock yet.