Programs do not usually run in Admin mode by default on operating systems with UAC, so your RealBand might not be able to write the activation information into the ticket file. Manually running the program as an Administrator will definitely fix this, as well as a number of other issues that can be caused by the program being unable to write to specific files.

It is recommended that you set both RealBand and Band-in-a-Box to always run as Administrator via right-clicking on the program icons and selecting Properties | Compatability | Run this program as an administrator.