All applications that run under XFree (the X11 port for Linux), seem to have the problem that the BackSpace key acts like the Delete key: they both delete the character after the cursor (they have the same key code). You can assign them the right key codes in a file called .Xmodmap in your home directory. Add to that file the following two lines (and restart X):
keycode 22 = BackSpace keycode 107 = Delete