I believe OOo experiences this same problem. When LO has focus, keyboard volume keys no longer work.
Steps to reproduce:
1. Play music on your computer (can be from anywhere, youtube, itunes, pandora, etc.)
2. Open Libreoffice (just to the startcenter is fine, but you can open writer or spreadsheet if you like)
3. If your keyboard is so equipped, try to use the keyboard volume keys to either raise or lower the volume. Nothing happens
4. Minimize LO
5. Try to use keyboard volume keys. They should now work.
Anytime the LO program has focus keyboard volume keys won't work.
thanks for the error report - we already know about this and status is tracke in bug 32664
*** This bug has been marked as a duplicate of bug 32664 ***