You have a variety of ways in which you can now install your themes into Sitemapper 6. Themes can also be installed individually or you can select multiple themes to install them at once.  

  • Double-click on any .CST file to install it.
  • Open Sitemapper and go to the File Menu > Import Theme Package.
  • Open Sitemapper, click on the Designer Toolbar Icon and then click the Green + sign.

If you have themes that were created with a proior version of Sitemapper, these themes are no longer compatible with Sitemapper.  While your first instinct will be to scream "unfair", this is actually a good thing.  
With version 6.x, we have made it so all themes are now responsive, which means they will look great on any device that accesses your sitemap (tablet, mobile phone, desktop).  To make all that work, the themes had to be recoded to support this new format.  Head over to 
http://www.coffeecup.com/store/themes to check them all out.