Its running Vista Business
We contacted sage and despite the fact that they claim Sage Line 50 is Vista certified they recomended that we downgrade back to XP.
Not only does UAC jump around like a looney when you open the program, but you also cannot enter any dates into the system, create data backups or perform many other standard functions.
So basically sage is not in anyway Vista compatible, and going on the previous catalogue of problems with their software I'd say its likely to be 2-3 years before they sort it out, no joke...
Post back if you have any more info, similar problems.
Ben
UK