I have installed Mapsource (under CrossOver Mac 6.0b1) in a new bottle and the application runs but the menus are all blank. The menus do show up, they just have no text so you can't tell what you are selecting if you click on an item.
I re-installed Mapsource in a new bottle with Internet Explorer 6, all fonts copied from a Windows machine and Microsoft System Installer installed as recommended by the 'Running Unsupported Applications in CrossOver' section (see http://www.codeweavers.com/support/docs/unsupported/) with the same results - blank menus.
I'll keep trying but if anyone has any suggestions of something to try let me know.