Occasionally, some users find a Tinderbox keyboard shortcut will fail to work. This may be because other apps running already have control of that shortcut. A good diagnostic start is to close all other apps and try again, as if the shortcut now works then the conflict is with one of those apps. Custom shortcuts can get added to the system so check System Preferences ▸ Keyboard ▸ Shortcuts and scan the list for conflicting assignments.
Harder to diagnose are conflicts with utilities that run in the background. If they have any visible presence it is often just an icon in the main menu bar, so easily overlooked. A good check for what background apps might be running is found via System Preferences ▸ Users & Groups ▸ [your username] in user list ▸ Login Items.
Known conflicts are with some of the default settings for 1Password's 'mini' applet. Because of how the latter operates it appears to trump Tinderbox's shortcuts for Note ▸ Make Web Link. If both apps are installed, depending on the users needs, either edit the shortcuts for 1Password Mini (in 1Password's Preferences) or use Tinderbox's menu items instead of the shortcut.