I can't get my CMB2 to run, either. Hope it gets fixed soon! All appeared to go smoothly with the installations and activation, but when I try to call up an instrument in Aria nothing happens -- what up with that?
Go to the folder where you installed the library COMB2. This folder is named "Garritan Concert and Marching Band 2". On the same level of this folder, you may see a folder named "Instruments". Just drag 'n drop the folder "Instruments" into the "Garritan Concert and Marching Band 2" folder. And the samples should load. At least it works for me. Now the samples are loading fine.
We're checking with the designers of the installer to see if we can't get a quick fix posted for this. Sorry for the inconvenience but glad that our ever-resourceful users are finding temporary work-arounds.