In addition to SaundraLD's helpful comments, I'd add this:
RoboSource Control was inherited by Adobe from the old eHelp Corporation and has not been modified since. There are some known issues when used on the increasingly popular Windows 7 64 bit machines. Therefore you would be advised to look at alternatives which Adobe has helpfully documented (see below).
It seems most new installations of Source Control for RoboHelp are turning to open source (free) applications like Subversion (with Tortoise SVN)
You can read an Adobe article on this here:
http://www.adobe.com/devnet/robohelp/articles/robohelp_subversion.html
Another alternative is explained by Mark Whisler (a well-known Forum contributor here!) in his article:
Integrating RoboHelp 9 projects with Perforce
http://www.adobe.com/devnet/robohelp/articles/perforce-integration.html
RoboHelp can also be used with Team Foundation Server if that is something your company is already using. A good article explaining this can be found here:
http://www.adobe.com/devnet/robohelp/articles/robohelp-tfs-integration.html
For the record, the RoboSource Control 3.1 (32 bit only) is still available and can be found here:
RoboSource Control can be installed from your DVD or unzipped download.
If you have TCS3, it will be found in \Add-ons\Adobe RoboHelp 9\RoboSource Control.
If you have RoboHelp 9, it will be found in \RoboSource Control.
Hope you will find these alternatives helpful.
John Daigle
Adobe Certified RoboHelp and Captivate Instructor
Evergreen, Colorado
www.showmethedemo.com