I see what you mean given that their current status on Vista is:
"(For Vista only. Please do NOT install this package on other versions of Windows. This Vista version has some functional limitations and less stable than the XP version due to the Vista's backward incompatibility.)"
"Q. Are you planning to make a Linux version of SA?
A. No. We do not have any plans for Linux at this moment."
"Q. Do you have a Mac or Palm version of SA?
A. No. we do not have a Mac and Palm version and do not have any plans for Mac or Palm versions of SA at this moment. If you run a Windows emulation on a Mac, SA should run on it."
"Q. Is SA compatible with Vista?
A. SA for Vista is available. Some features such as z39.50 might not work on Vista."
On the other hand
"Q. Any future development plan?
A. Sync&Share, Project, and SA5."
I would assume that this company is very slow in adopting change. They may eventually make a fully Vista/7 compatible version at some point but right now it seems XP is greatly favoured. Hence you are kind of locked into old versions of Windows if you want to use this program. Given their preference for XP it may be best to use XP Mode or install XP in VirtualBox for use of this program.
I guess you have invested alot of time into this program. Its capabilities seem very similar to EndNote from first glance.
I recommend you to give Mendeley Desktop a try it is cross-platform and has a much wider range of users. It is seems to have much more support, is very easy to use. As it has such a large user base bugs are quickly submitted to the team and fixed with very regular updates. Unfortunately they or Mathtype don't fully support the 64 bit version of Office but both are due to release beta versions that do some time next month.