VeSys is a 32bit application and so would need to run within a 32bit version of AutoCAD. I've heard of this issue before but I believe it is still possible to install AutoCAD 2008 as either a 32bit on a 64bit machine, AutoCAD 2009 is more problematic as it is always wants to install as 64bit.
For VeSys users the 64bit version of AutoCAD is not necessary the largest designs I've seen are only around 15mb.
I have been unable to force Win7 to install the 32 bit version. The error message "32bit version can not be installed on 64 bit" is the machine's only response.
I had selected a 64 bit PC to get the most of of SolidWorks 2010. We have CAD 2009 and 2010, but haven't installed either due to VeSys 2008.2 requirements.
I think we may have to re-install a 32bit version of Windows onto this machine unless there is some way to add the XP Mode 'machine' onto our network. IT didn't think it would work that way.