What version of Windows 7 do you have? If you have professional or ultimate and your CPU can do virtualization, then you can install Windows XP Mode and that should allow it to work.
If your CPU cannot do virtualization, all is not lost. You can get VMWare Player, Virtual PC or Virtual Box (all free) to install a copy of XP or Windows 95/95/ME on your machine and then install the software that way.
To check if you can run Windows XP Mode, go here ->
http://www.microsoft.com/windows/virtual-pc/download.aspx
This will determine if your PC can run Windows XP Mode (it checks your OS as well as allows you to run a program to see if your CPU can do virtualization).
Again, if it cannot run Windows XP Mode, then you can download one of the other three packages I stated. I recommend VMWare Player first and then Virtual Box next. However, with these programs, you will have to already own a licensed copy of 95/98/Me/XP whereas with Windows XP Mode, Microsoft provides you with a copy of XP in virtual hard drive format for Virtual PC.