There is nowhere specified that you can't run the software in Windows 7. Also I have done some search over the web and found from the main developers that the software will work correctly on Windows 7 besides a few minor issues like the help file won't start or the speed is a little slower than the current improved versions. Although they didn't clearly specify that you should use version 7.0 with Windows 7, they also mentioned that an upgrade to 8.0 is recommended because it supports Windows 7 and Vista and the processing and working speed is 20 times better, at least. If something is not working, try and install it under Windows 7 and use the Compatibility solution when you right click on executable and choose Properties
then Compatibility
tab and from the drop down menu select Windows XP.
My advice is to try and upgrade to version 8.0 because as mentioned the next upgrade version is free and brings many new features and benefits especially if you'll be using Windows 7 for a long time.