The skip forward and backward buttons work on gtcd but the keyboard
bindings "+" and "-" don't work. I tried rebinding them to other keys with
no luck. I was able to rebind the other actions successfully.
I glanced at the source code and it seems that the problem may be in gtcd.c
in fn skip_cb() The function has conditionalals that check for mouse
presses and releases but it seems to ignore keystrokes.
This is fixed in GNOME CVS since 31 of May.
Resolved upstream, we have the latest tarball from there.