Maybe it is caused by other program that i installed, suddenly when i wanted to start my gnome terminal in panel my terminal wont start.
To solve this i did these steps,
0. Restart Backtrack dont start X (X-windows) yet.
1. Uninstall latest program/application i installed.
apt-get remove programname
2. Uninstall my gnome-manager.
apt-get remove gnome-manager
3. Reinstall gnome-manager.
apt-get install gnome-manager
4. When finished i start Gnome by command startx and the terminal now works as usual.