Hi BilliBono, welcome to the wonderful world of illogical WMDC issues with Vista!
Many users are reporting a variety of issues but none appear to be the same!
First thing I would try is to remove all partnership data from the PC and remove the Partnership from the device under the ActiveSync/Menu options. Reboot PC and soft-reset the Orbit and try again.
As to WM6.1 ROMs, there are no official ones but
XDA-Devs may have something in the Artemis Upgrading section of the forums. Have a good read BEFORE attempting anything as you will need to follow a set procedure by updating the SPL before the ROM.