I suspect that Fireworks is being overwhelmed by the number of textures on your server, or doesn't like the location of the textures folder. In older versions of Fireworks you could reset all the preferences back to their defaults by deleting the Fireworks preferences text file, which rebuilt itself as soon as the program reloaded. I'm not sure if that is still available in CS6.
Preference can be deleted and reloaded even in CS6.Please delete the file from the location C:\Users\<userName>\AppData\Roaming\Adobe\Fireworks CS6\English\Fireworks CS6 Preferences.txt.
After relaunching the application preferences will be reloaded.Textures folder that you are using might have large number of textures.Try to keep a smaller set of textures and see if the application launches fine.